you-draw-it

README.MD

Early/simplifed version of You Draw It: What Got Better or Worse During Obama’s Presidency

d3.drag is pretty great!

_script.js

var data = [
  {"year": 2001,    "debt": 31.4},
  {"year": 2002,    "debt": 32.6},
  {"year": 2003,    "debt": 34.5},
  {"year": 2004,    "debt": 35.5},
  {"year": 2005,    "debt": 35.6},
  {"year": 2006,    "debt": 35.3},
  {"year": 2007,    "debt": 35.2},
  {"year": 2008,    "debt": 39.3},
  {"year": 2009,    "debt": 52.3},
  {"year": 2010,    "debt": 60.9},
  {"year": 2011,    "debt": 65.9},
  {"year": 2012,    "debt": 70.4},
  {"year": 2013,    "debt": 72.6},
  {"year": 2014,    "debt": 74.4},
  {"year": 2015,    "debt": 73.6},
]

var ƒ = d3.f

var sel = d3.select('body').html('')
var c = d3.conventions({
  parentSel: sel, 
  totalWidth: sel.node().offsetWidth, 
  height: 400, 
  margin: {left: 50, right: 50, top: 30, bottom: 30}
})

c.svg.append('rect').at({width: c.width, height: c.height, opacity: 0})

c.x.domain([2001, 2015])
c.y.domain([0, 100])

c.xAxis.ticks(4).tickFormat(ƒ())
c.yAxis.ticks(5).tickFormat(d => d + '%')

var area = d3.area().x(ƒ('year', c.x)).y0(ƒ('debt', c.y)).y1(c.height)
var line = d3.area().x(ƒ('year', c.x)).y(ƒ('debt', c.y))

var clipRect = c.svg
  .append('clipPath#clip')
  .append('rect')
  .at({width: c.x(2008) - 2, height: c.height})

var correctSel = c.svg.append('g').attr('clip-path', 'url(#clip)')

correctSel.append('path.area').at({d: area(data)})
correctSel.append('path.line').at({d: line(data)})
yourDataSel = c.svg.append('path.your-line')

c.drawAxis()

yourData = data
  .map(function(d){ return {year: d.year, debt: d.debt, defined: 0} })
  .filter(function(d){
    if (d.year == 2008) d.defined = true
    return d.year >= 2008
  })

var completed = false

var drag = d3.drag()
  .on('drag', function(){
    var pos = d3.mouse(this)
    var year = clamp(2009, 2016, c.x.invert(pos[0]))
    var debt = clamp(0, c.y.domain()[1], c.y.invert(pos[1]))

    yourData.forEach(function(d){
      if (Math.abs(d.year - year) < .5){
        d.debt = debt
        d.defined = true
      }
    })

    yourDataSel.at({d: line.defined(ƒ('defined'))(yourData)})

    if (!completed && d3.mean(yourData, ƒ('defined')) == 1){
      completed = true
      clipRect.transition().duration(1000).attr('width', c.x(2015))
    }
  })

c.svg.call(drag)



function clamp(a, b, c){ return Math.max(a, Math.min(b, c)) }

d3v4.js

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (factory((global.d3 = global.d3 || {})));
}(this, function (exports) { 'use strict';

  function ascending(a, b) {
    return a < b ? -1 : a > b ? 1 : a >= b ? 0 : NaN;
  }

  function bisector(compare) {
    if (compare.length === 1) compare = ascendingComparator(compare);
    return {
      left: function(a, x, lo, hi) {
        if (lo == null) lo = 0;
        if (hi == null) hi = a.length;
        while (lo < hi) {
          var mid = lo + hi >>> 1;
          if (compare(a[mid], x) < 0) lo = mid + 1;
          else hi = mid;
        }
        return lo;
      },
      right: function(a, x, lo, hi) {
        if (lo == null) lo = 0;
        if (hi == null) hi = a.length;
        while (lo < hi) {
          var mid = lo + hi >>> 1;
          if (compare(a[mid], x) > 0) hi = mid;
          else lo = mid + 1;
        }
        return lo;
      }
    };
  }

  function ascendingComparator(f) {
    return function(d, x) {
      return ascending(f(d), x);
    };
  }

  var ascendingBisect = bisector(ascending);
  var bisectRight = ascendingBisect.right;
  var bisectLeft = ascendingBisect.left;

  function descending(a, b) {
    return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
  }

  function number(x) {
    return x === null ? NaN : +x;
  }

  function variance(array, f) {
    var n = array.length,
        m = 0,
        a,
        d,
        s = 0,
        i = -1,
        j = 0;

    if (f == null) {
      while (++i < n) {
        if (!isNaN(a = number(array[i]))) {
          d = a - m;
          m += d / ++j;
          s += d * (a - m);
        }
      }
    }

    else {
      while (++i < n) {
        if (!isNaN(a = number(f(array[i], i, array)))) {
          d = a - m;
          m += d / ++j;
          s += d * (a - m);
        }
      }
    }

    if (j > 1) return s / (j - 1);
  }

  function deviation(array, f) {
    var v = variance(array, f);
    return v ? Math.sqrt(v) : v;
  }

  function extent(array, f) {
    var i = -1,
        n = array.length,
        a,
        b,
        c;

    if (f == null) {
      while (++i < n) if ((b = array[i]) != null && b >= b) { a = c = b; break; }
      while (++i < n) if ((b = array[i]) != null) {
        if (a > b) a = b;
        if (c < b) c = b;
      }
    }

    else {
      while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = c = b; break; }
      while (++i < n) if ((b = f(array[i], i, array)) != null) {
        if (a > b) a = b;
        if (c < b) c = b;
      }
    }

    return [a, c];
  }

  var array = Array.prototype;

  var slice = array.slice;
  var map = array.map;

  function constant(x) {
    return function() {
      return x;
    };
  }

  function identity(x) {
    return x;
  }

  function range(start, stop, step) {
    start = +start, stop = +stop, step = (n = arguments.length) < 2 ? (stop = start, start = 0, 1) : n < 3 ? 1 : +step;

    var i = -1,
        n = Math.max(0, Math.ceil((stop - start) / step)) | 0,
        range = new Array(n);

    while (++i < n) {
      range[i] = start + i * step;
    }

    return range;
  }

  var e10 = Math.sqrt(50);
  var e5 = Math.sqrt(10);
  var e2 = Math.sqrt(2);
  function ticks(start, stop, count) {
    var step = tickStep(start, stop, count);
    return range(
      Math.ceil(start / step) * step,
      Math.floor(stop / step) * step + step / 2, // inclusive
      step
    );
  }

  function tickStep(start, stop, count) {
    var step0 = Math.abs(stop - start) / Math.max(0, count),
        step1 = Math.pow(10, Math.floor(Math.log(step0) / Math.LN10)),
        error = step0 / step1;
    if (error >= e10) step1 *= 10;
    else if (error >= e5) step1 *= 5;
    else if (error >= e2) step1 *= 2;
    return stop < start ? -step1 : step1;
  }

  function sturges(values) {
    return Math.ceil(Math.log(values.length) / Math.LN2) + 1;
  }

  function histogram() {
    var value = identity,
        domain = extent,
        threshold = sturges;

    function histogram(data) {
      var i,
          n = data.length,
          x,
          values = new Array(n);

      for (i = 0; i < n; ++i) {
        values[i] = value(data[i], i, data);
      }

      var xz = domain(values),
          x0 = xz[0],
          x1 = xz[1],
          tz = threshold(values, x0, x1);

      // Convert number of thresholds into uniform thresholds.
      if (!Array.isArray(tz)) tz = ticks(x0, x1, tz);

      // Remove any thresholds outside the domain.
      var m = tz.length;
      while (tz[0] <= x0) tz.shift(), --m;
      while (tz[m - 1] >= x1) tz.pop(), --m;

      var bins = new Array(m + 1),
          bin;

      // Initialize bins.
      for (i = 0; i <= m; ++i) {
        bin = bins[i] = [];
        bin.x0 = i > 0 ? tz[i - 1] : x0;
        bin.x1 = i < m ? tz[i] : x1;
      }

      // Assign data to bins by value, ignoring any outside the domain.
      for (i = 0; i < n; ++i) {
        x = values[i];
        if (x0 <= x && x <= x1) {
          bins[bisectRight(tz, x, 0, m)].push(data[i]);
        }
      }

      return bins;
    }

    histogram.value = function(_) {
      return arguments.length ? (value = typeof _ === "function" ? _ : constant(_), histogram) : value;
    };

    histogram.domain = function(_) {
      return arguments.length ? (domain = typeof _ === "function" ? _ : constant([_[0], _[1]]), histogram) : domain;
    };

    histogram.thresholds = function(_) {
      return arguments.length ? (threshold = typeof _ === "function" ? _ : Array.isArray(_) ? constant(slice.call(_)) : constant(_), histogram) : threshold;
    };

    return histogram;
  }

  function threshold(array, p, f) {
    if (f == null) f = number;
    if (!(n = array.length)) return;
    if ((p = +p) <= 0 || n < 2) return +f(array[0], 0, array);
    if (p >= 1) return +f(array[n - 1], n - 1, array);
    var n,
        h = (n - 1) * p,
        i = Math.floor(h),
        a = +f(array[i], i, array),
        b = +f(array[i + 1], i + 1, array);
    return a + (b - a) * (h - i);
  }

  function freedmanDiaconis(values, min, max) {
    values = map.call(values, number).sort(ascending);
    return Math.ceil((max - min) / (2 * (threshold(values, 0.75) - threshold(values, 0.25)) * Math.pow(values.length, -1 / 3)));
  }

  function scott(values, min, max) {
    return Math.ceil((max - min) / (3.5 * deviation(values) * Math.pow(values.length, -1 / 3)));
  }

  function max(array, f) {
    var i = -1,
        n = array.length,
        a,
        b;

    if (f == null) {
      while (++i < n) if ((b = array[i]) != null && b >= b) { a = b; break; }
      while (++i < n) if ((b = array[i]) != null && b > a) a = b;
    }

    else {
      while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = b; break; }
      while (++i < n) if ((b = f(array[i], i, array)) != null && b > a) a = b;
    }

    return a;
  }

  function mean(array, f) {
    var s = 0,
        n = array.length,
        a,
        i = -1,
        j = n;

    if (f == null) {
      while (++i < n) if (!isNaN(a = number(array[i]))) s += a; else --j;
    }

    else {
      while (++i < n) if (!isNaN(a = number(f(array[i], i, array)))) s += a; else --j;
    }

    if (j) return s / j;
  }

  function median(array, f) {
    var numbers = [],
        n = array.length,
        a,
        i = -1;

    if (f == null) {
      while (++i < n) if (!isNaN(a = number(array[i]))) numbers.push(a);
    }

    else {
      while (++i < n) if (!isNaN(a = number(f(array[i], i, array)))) numbers.push(a);
    }

    return threshold(numbers.sort(ascending), 0.5);
  }

  function merge(arrays) {
    var n = arrays.length,
        m,
        i = -1,
        j = 0,
        merged,
        array;

    while (++i < n) j += arrays[i].length;
    merged = new Array(j);

    while (--n >= 0) {
      array = arrays[n];
      m = array.length;
      while (--m >= 0) {
        merged[--j] = array[m];
      }
    }

    return merged;
  }

  function min(array, f) {
    var i = -1,
        n = array.length,
        a,
        b;

    if (f == null) {
      while (++i < n) if ((b = array[i]) != null && b >= b) { a = b; break; }
      while (++i < n) if ((b = array[i]) != null && a > b) a = b;
    }

    else {
      while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = b; break; }
      while (++i < n) if ((b = f(array[i], i, array)) != null && a > b) a = b;
    }

    return a;
  }

  function pairs(array) {
    var i = 0, n = array.length - 1, p = array[0], pairs = new Array(n < 0 ? 0 : n);
    while (i < n) pairs[i] = [p, p = array[++i]];
    return pairs;
  }

  function permute(array, indexes) {
    var i = indexes.length, permutes = new Array(i);
    while (i--) permutes[i] = array[indexes[i]];
    return permutes;
  }

  function scan(array, compare) {
    if (!(n = array.length)) return;
    var i = 0,
        n,
        j = 0,
        xi,
        xj = array[j];

    if (!compare) compare = ascending;

    while (++i < n) if (compare(xi = array[i], xj) < 0 || compare(xj, xj) !== 0) xj = xi, j = i;

    if (compare(xj, xj) === 0) return j;
  }

  function shuffle(array, i0, i1) {
    var m = (i1 == null ? array.length : i1) - (i0 = i0 == null ? 0 : +i0),
        t,
        i;

    while (m) {
      i = Math.random() * m-- | 0;
      t = array[m + i0];
      array[m + i0] = array[i + i0];
      array[i + i0] = t;
    }

    return array;
  }

  function sum(array, f) {
    var s = 0,
        n = array.length,
        a,
        i = -1;

    if (f == null) {
      while (++i < n) if (a = +array[i]) s += a; // Note: zero and null are equivalent.
    }

    else {
      while (++i < n) if (a = +f(array[i], i, array)) s += a;
    }

    return s;
  }

  function transpose(matrix) {
    if (!(n = matrix.length)) return [];
    for (var i = -1, m = min(matrix, length), transpose = new Array(m); ++i < m;) {
      for (var j = -1, n, row = transpose[i] = new Array(n); ++j < n;) {
        row[j] = matrix[j][i];
      }
    }
    return transpose;
  }

  function length(d) {
    return d.length;
  }

  function zip() {
    return transpose(arguments);
  }

  var prefix = "$";

  function Map() {}

  Map.prototype = map$1.prototype = {
    constructor: Map,
    has: function(key) {
      return (prefix + key) in this;
    },
    get: function(key) {
      return this[prefix + key];
    },
    set: function(key, value) {
      this[prefix + key] = value;
      return this;
    },
    remove: function(key) {
      var property = prefix + key;
      return property in this && delete this[property];
    },
    clear: function() {
      for (var property in this) if (property[0] === prefix) delete this[property];
    },
    keys: function() {
      var keys = [];
      for (var property in this) if (property[0] === prefix) keys.push(property.slice(1));
      return keys;
    },
    values: function() {
      var values = [];
      for (var property in this) if (property[0] === prefix) values.push(this[property]);
      return values;
    },
    entries: function() {
      var entries = [];
      for (var property in this) if (property[0] === prefix) entries.push({key: property.slice(1), value: this[property]});
      return entries;
    },
    size: function() {
      var size = 0;
      for (var property in this) if (property[0] === prefix) ++size;
      return size;
    },
    empty: function() {
      for (var property in this) if (property[0] === prefix) return false;
      return true;
    },
    each: function(f) {
      for (var property in this) if (property[0] === prefix) f(this[property], property.slice(1), this);
    }
  };

  function map$1(object, f) {
    var map = new Map;

    // Copy constructor.
    if (object instanceof Map) object.each(function(value, key) { map.set(key, value); });

    // Index array by numeric index or specified key function.
    else if (Array.isArray(object)) {
      var i = -1,
          n = object.length,
          o;

      if (f == null) while (++i < n) map.set(i, object[i]);
      else while (++i < n) map.set(f(o = object[i], i, object), o);
    }

    // Convert object to map.
    else if (object) for (var key in object) map.set(key, object[key]);

    return map;
  }

  function nest() {
    var keys = [],
        sortKeys = [],
        sortValues,
        rollup,
        nest;

    function apply(array, depth, createResult, setResult) {
      if (depth >= keys.length) return rollup != null
          ? rollup(array) : (sortValues != null
          ? array.sort(sortValues)
          : array);

      var i = -1,
          n = array.length,
          key = keys[depth++],
          keyValue,
          value,
          valuesByKey = map$1(),
          values,
          result = createResult();

      while (++i < n) {
        if (values = valuesByKey.get(keyValue = key(value = array[i]) + "")) {
          values.push(value);
        } else {
          valuesByKey.set(keyValue, [value]);
        }
      }

      valuesByKey.each(function(values, key) {
        setResult(result, key, apply(values, depth, createResult, setResult));
      });

      return result;
    }

    function entries(map, depth) {
      if (++depth > keys.length) return map;
      var array, sortKey = sortKeys[depth - 1];
      if (rollup != null && depth >= keys.length) array = map.entries();
      else array = [], map.each(function(v, k) { array.push({key: k, values: entries(v, depth)}); });
      return sortKey != null ? array.sort(function(a, b) { return sortKey(a.key, b.key); }) : array;
    }

    return nest = {
      object: function(array) { return apply(array, 0, createObject, setObject); },
      map: function(array) { return apply(array, 0, createMap, setMap); },
      entries: function(array) { return entries(apply(array, 0, createMap, setMap), 0); },
      key: function(d) { keys.push(d); return nest; },
      sortKeys: function(order) { sortKeys[keys.length - 1] = order; return nest; },
      sortValues: function(order) { sortValues = order; return nest; },
      rollup: function(f) { rollup = f; return nest; }
    };
  }

  function createObject() {
    return {};
  }

  function setObject(object, key, value) {
    object[key] = value;
  }

  function createMap() {
    return map$1();
  }

  function setMap(map, key, value) {
    map.set(key, value);
  }

  function Set() {}

  var proto = map$1.prototype;

  Set.prototype = set.prototype = {
    constructor: Set,
    has: proto.has,
    add: function(value) {
      value += "";
      this[prefix + value] = value;
      return this;
    },
    remove: proto.remove,
    clear: proto.clear,
    values: proto.keys,
    size: proto.size,
    empty: proto.empty,
    each: proto.each
  };

  function set(object, f) {
    var set = new Set;

    // Copy constructor.
    if (object instanceof Set) object.each(function(value) { set.add(value); });

    // Otherwise, assume it’s an array.
    else if (object) {
      var i = -1, n = object.length;
      if (f == null) while (++i < n) set.add(object[i]);
      else while (++i < n) set.add(f(object[i], i, object));
    }

    return set;
  }

  function d3keys(map) {
    var keys = [];
    for (var key in map) keys.push(key);
    return keys;
  }

  function values(map) {
    var values = [];
    for (var key in map) values.push(map[key]);
    return values;
  }

  function entries(map) {
    var entries = [];
    for (var key in map) entries.push({key: key, value: map[key]});
    return entries;
  }

  function uniform(min, max) {
    min = min == null ? 0 : +min;
    max = max == null ? 1 : +max;
    if (arguments.length === 1) max = min, min = 0;
    else max -= min;
    return function() {
      return Math.random() * max + min;
    };
  }

  function normal(mu, sigma) {
    var x, r;
    mu = mu == null ? 0 : +mu;
    sigma = sigma == null ? 1 : +sigma;
    return function() {
      var y;

      // If available, use the second previously-generated uniform random.
      if (x != null) y = x, x = null;

      // Otherwise, generate a new x and y.
      else do {
        x = Math.random() * 2 - 1;
        y = Math.random() * 2 - 1;
        r = x * x + y * y;
      } while (!r || r > 1);

      return mu + sigma * y * Math.sqrt(-2 * Math.log(r) / r);
    };
  }

  function logNormal() {
    var randomNormal = normal.apply(this, arguments);
    return function() {
      return Math.exp(randomNormal());
    };
  }

  function irwinHall(n) {
    return function() {
      for (var sum = 0, i = 0; i < n; ++i) sum += Math.random();
      return sum;
    };
  }

  function bates(n) {
    var randomIrwinHall = irwinHall(n);
    return function() {
      return randomIrwinHall() / n;
    };
  }

  function exponential(lambda) {
    return function() {
      return -Math.log(1 - Math.random()) / lambda;
    };
  }

  function linear(t) {
    return +t;
  }

  function quadIn(t) {
    return t * t;
  }

  function quadOut(t) {
    return t * (2 - t);
  }

  function quadInOut(t) {
    return ((t *= 2) <= 1 ? t * t : --t * (2 - t) + 1) / 2;
  }

  function cubicIn(t) {
    return t * t * t;
  }

  function cubicOut(t) {
    return --t * t * t + 1;
  }

  function easeCubicInOut(t) {
    return ((t *= 2) <= 1 ? t * t * t : (t -= 2) * t * t + 2) / 2;
  }

  var exponent = 3;

  var polyIn = (function custom(e) {
    e = +e;

    function polyIn(t) {
      return Math.pow(t, e);
    }

    polyIn.exponent = custom;

    return polyIn;
  })(exponent);

  var polyOut = (function custom(e) {
    e = +e;

    function polyOut(t) {
      return 1 - Math.pow(1 - t, e);
    }

    polyOut.exponent = custom;

    return polyOut;
  })(exponent);

  var polyInOut = (function custom(e) {
    e = +e;

    function polyInOut(t) {
      return ((t *= 2) <= 1 ? Math.pow(t, e) : 2 - Math.pow(2 - t, e)) / 2;
    }

    polyInOut.exponent = custom;

    return polyInOut;
  })(exponent);

  var pi = Math.PI;
  var halfPi = pi / 2;
  function sinIn(t) {
    return 1 - Math.cos(t * halfPi);
  }

  function sinOut(t) {
    return Math.sin(t * halfPi);
  }

  function sinInOut(t) {
    return (1 - Math.cos(pi * t)) / 2;
  }

  function expIn(t) {
    return Math.pow(2, 10 * t - 10);
  }

  function expOut(t) {
    return 1 - Math.pow(2, -10 * t);
  }

  function expInOut(t) {
    return ((t *= 2) <= 1 ? Math.pow(2, 10 * t - 10) : 2 - Math.pow(2, 10 - 10 * t)) / 2;
  }

  function circleIn(t) {
    return 1 - Math.sqrt(1 - t * t);
  }

  function circleOut(t) {
    return Math.sqrt(1 - --t * t);
  }

  function circleInOut(t) {
    return ((t *= 2) <= 1 ? 1 - Math.sqrt(1 - t * t) : Math.sqrt(1 - (t -= 2) * t) + 1) / 2;
  }

  var b1 = 4 / 11;
  var b2 = 6 / 11;
  var b3 = 8 / 11;
  var b4 = 3 / 4;
  var b5 = 9 / 11;
  var b6 = 10 / 11;
  var b7 = 15 / 16;
  var b8 = 21 / 22;
  var b9 = 63 / 64;
  var b0 = 1 / b1 / b1;
  function bounceIn(t) {
    return 1 - bounceOut(1 - t);
  }

  function bounceOut(t) {
    return (t = +t) < b1 ? b0 * t * t : t < b3 ? b0 * (t -= b2) * t + b4 : t < b6 ? b0 * (t -= b5) * t + b7 : b0 * (t -= b8) * t + b9;
  }

  function bounceInOut(t) {
    return ((t *= 2) <= 1 ? 1 - bounceOut(1 - t) : bounceOut(t - 1) + 1) / 2;
  }

  var overshoot = 1.70158;

  var backIn = (function custom(s) {
    s = +s;

    function backIn(t) {
      return t * t * ((s + 1) * t - s);
    }

    backIn.overshoot = custom;

    return backIn;
  })(overshoot);

  var backOut = (function custom(s) {
    s = +s;

    function backOut(t) {
      return --t * t * ((s + 1) * t + s) + 1;
    }

    backOut.overshoot = custom;

    return backOut;
  })(overshoot);

  var backInOut = (function custom(s) {
    s = +s;

    function backInOut(t) {
      return ((t *= 2) < 1 ? t * t * ((s + 1) * t - s) : (t -= 2) * t * ((s + 1) * t + s) + 2) / 2;
    }

    backInOut.overshoot = custom;

    return backInOut;
  })(overshoot);

  var tau = 2 * Math.PI;
  var amplitude = 1;
  var period = 0.3;
  var elasticIn = (function custom(a, p) {
    var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);

    function elasticIn(t) {
      return a * Math.pow(2, 10 * --t) * Math.sin((s - t) / p);
    }

    elasticIn.amplitude = function(a) { return custom(a, p * tau); };
    elasticIn.period = function(p) { return custom(a, p); };

    return elasticIn;
  })(amplitude, period);

  var elasticOut = (function custom(a, p) {
    var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);

    function elasticOut(t) {
      return 1 - a * Math.pow(2, -10 * (t = +t)) * Math.sin((t + s) / p);
    }

    elasticOut.amplitude = function(a) { return custom(a, p * tau); };
    elasticOut.period = function(p) { return custom(a, p); };

    return elasticOut;
  })(amplitude, period);

  var elasticInOut = (function custom(a, p) {
    var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);

    function elasticInOut(t) {
      return ((t = t * 2 - 1) < 0
          ? a * Math.pow(2, 10 * t) * Math.sin((s - t) / p)
          : 2 - a * Math.pow(2, -10 * t) * Math.sin((s + t) / p)) / 2;
    }

    elasticInOut.amplitude = function(a) { return custom(a, p * tau); };
    elasticInOut.period = function(p) { return custom(a, p); };

    return elasticInOut;
  })(amplitude, period);

  function area(polygon) {
    var i = -1,
        n = polygon.length,
        a,
        b = polygon[n - 1],
        area = 0;

    while (++i < n) {
      a = b;
      b = polygon[i];
      area += a[1] * b[0] - a[0] * b[1];
    }

    return area / 2;
  }

  function centroid(polygon) {
    var i = -1,
        n = polygon.length,
        x = 0,
        y = 0,
        a,
        b = polygon[n - 1],
        c,
        k = 0;

    while (++i < n) {
      a = b;
      b = polygon[i];
      k += c = a[0] * b[1] - b[0] * a[1];
      x += (a[0] + b[0]) * c;
      y += (a[1] + b[1]) * c;
    }

    return k *= 3, [x / k, y / k];
  }

  // Returns the 2D cross product of AB and AC vectors, i.e., the z-component of
  // the 3D cross product in a quadrant I Cartesian coordinate system (+x is
  // right, +y is up). Returns a positive value if ABC is counter-clockwise,
  // negative if clockwise, and zero if the points are collinear.
  function cross(a, b, c) {
    return (b[0] - a[0]) * (c[1] - a[1]) - (b[1] - a[1]) * (c[0] - a[0]);
  }

  function lexicographicOrder(a, b) {
    return a[0] - b[0] || a[1] - b[1];
  }

  // Computes the upper convex hull per the monotone chain algorithm.
  // Assumes points.length >= 3, is sorted by x, unique in y.
  // Returns an array of indices into points in left-to-right order.
  function computeUpperHullIndexes(points) {
    var n = points.length,
        indexes = [0, 1],
        size = 2;

    for (var i = 2; i < n; ++i) {
      while (size > 1 && cross(points[indexes[size - 2]], points[indexes[size - 1]], points[i]) <= 0) --size;
      indexes[size++] = i;
    }

    return indexes.slice(0, size); // remove popped points
  }

  function hull(points) {
    if ((n = points.length) < 3) return null;

    var i,
        n,
        sortedPoints = new Array(n),
        flippedPoints = new Array(n);

    for (i = 0; i < n; ++i) sortedPoints[i] = [+points[i][0], +points[i][1], i];
    sortedPoints.sort(lexicographicOrder);
    for (i = 0; i < n; ++i) flippedPoints[i] = [sortedPoints[i][0], -sortedPoints[i][1]];

    var upperIndexes = computeUpperHullIndexes(sortedPoints),
        lowerIndexes = computeUpperHullIndexes(flippedPoints);

    // Construct the hull polygon, removing possible duplicate endpoints.
    var skipLeft = lowerIndexes[0] === upperIndexes[0],
        skipRight = lowerIndexes[lowerIndexes.length - 1] === upperIndexes[upperIndexes.length - 1],
        hull = [];

    // Add upper hull in right-to-l order.
    // Then add lower hull in left-to-right order.
    for (i = upperIndexes.length - 1; i >= 0; --i) hull.push(points[sortedPoints[upperIndexes[i]][2]]);
    for (i = +skipLeft; i < lowerIndexes.length - skipRight; ++i) hull.push(points[sortedPoints[lowerIndexes[i]][2]]);

    return hull;
  }

  function contains(polygon, point) {
    var n = polygon.length,
        p = polygon[n - 1],
        x = point[0], y = point[1],
        x0 = p[0], y0 = p[1],
        x1, y1,
        inside = false;

    for (var i = 0; i < n; ++i) {
      p = polygon[i], x1 = p[0], y1 = p[1];
      if (((y1 > y) !== (y0 > y)) && (x < (x0 - x1) * (y - y1) / (y0 - y1) + x1)) inside = !inside;
      x0 = x1, y0 = y1;
    }

    return inside;
  }

  function length$1(polygon) {
    var i = -1,
        n = polygon.length,
        b = polygon[n - 1],
        xa,
        ya,
        xb = b[0],
        yb = b[1],
        perimeter = 0;

    while (++i < n) {
      xa = xb;
      ya = yb;
      b = polygon[i];
      xb = b[0];
      yb = b[1];
      xa -= xb;
      ya -= yb;
      perimeter += Math.sqrt(xa * xa + ya * ya);
    }

    return perimeter;
  }

var   pi$1 = Math.PI;
var   tau$1 = 2 * pi$1;
  var epsilon = 1e-6;
  var tauEpsilon = tau$1 - epsilon;
  function Path() {
    this._x0 = this._y0 = // start of current subpath
    this._x1 = this._y1 = null; // end of current subpath
    this._ = [];
  }

  function path() {
    return new Path;
  }

  Path.prototype = path.prototype = {
    constructor: Path,
    moveTo: function(x, y) {
      this._.push("M", this._x0 = this._x1 = +x, ",", this._y0 = this._y1 = +y);
    },
    closePath: function() {
      if (this._x1 !== null) {
        this._x1 = this._x0, this._y1 = this._y0;
        this._.push("Z");
      }
    },
    lineTo: function(x, y) {
      this._.push("L", this._x1 = +x, ",", this._y1 = +y);
    },
    quadraticCurveTo: function(x1, y1, x, y) {
      this._.push("Q", +x1, ",", +y1, ",", this._x1 = +x, ",", this._y1 = +y);
    },
    bezierCurveTo: function(x1, y1, x2, y2, x, y) {
      this._.push("C", +x1, ",", +y1, ",", +x2, ",", +y2, ",", this._x1 = +x, ",", this._y1 = +y);
    },
    arcTo: function(x1, y1, x2, y2, r) {
      x1 = +x1, y1 = +y1, x2 = +x2, y2 = +y2, r = +r;
      var x0 = this._x1,
          y0 = this._y1,
          x21 = x2 - x1,
          y21 = y2 - y1,
          x01 = x0 - x1,
          y01 = y0 - y1,
          l01_2 = x01 * x01 + y01 * y01;

      // Is the radius negative? Error.
      if (r < 0) throw new Error("negative radius: " + r);

      // Is this path empty? Move to (x1,y1).
      if (this._x1 === null) {
        this._.push(
          "M", this._x1 = x1, ",", this._y1 = y1
        );
      }

      // Or, is (x1,y1) coincident with (x0,y0)? Do nothing.
      else if (!(l01_2 > epsilon));

      // Or, are (x0,y0), (x1,y1) and (x2,y2) collinear?
      // Equivalently, is (x1,y1) coincident with (x2,y2)?
      // Or, is the radius zero? Line to (x1,y1).
      else if (!(Math.abs(y01 * x21 - y21 * x01) > epsilon) || !r) {
        this._.push(
          "L", this._x1 = x1, ",", this._y1 = y1
        );
      }

      // Otherwise, draw an arc!
      else {
        var x20 = x2 - x0,
            y20 = y2 - y0,
            l21_2 = x21 * x21 + y21 * y21,
            l20_2 = x20 * x20 + y20 * y20,
            l21 = Math.sqrt(l21_2),
            l01 = Math.sqrt(l01_2),
            l = r * Math.tan((pi$1 - Math.acos((l21_2 + l01_2 - l20_2) / (2 * l21 * l01))) / 2),
            t01 = l / l01,
            t21 = l / l21;

        // If the start tangent is not coincident with (x0,y0), line to.
        if (Math.abs(t01 - 1) > epsilon) {
          this._.push(
            "L", x1 + t01 * x01, ",", y1 + t01 * y01
          );
        }

        this._.push(
          "A", r, ",", r, ",0,0,", +(y01 * x20 > x01 * y20), ",", this._x1 = x1 + t21 * x21, ",", this._y1 = y1 + t21 * y21
        );
      }
    },
    arc: function(x, y, r, a0, a1, ccw) {
      x = +x, y = +y, r = +r;
      var dx = r * Math.cos(a0),
          dy = r * Math.sin(a0),
          x0 = x + dx,
          y0 = y + dy,
          cw = 1 ^ ccw,
          da = ccw ? a0 - a1 : a1 - a0;

      // Is the radius negative? Error.
      if (r < 0) throw new Error("negative radius: " + r);

      // Is this path empty? Move to (x0,y0).
      if (this._x1 === null) {
        this._.push(
          "M", x0, ",", y0
        );
      }

      // Or, is (x0,y0) not coincident with the previous point? Line to (x0,y0).
      else if (Math.abs(this._x1 - x0) > epsilon || Math.abs(this._y1 - y0) > epsilon) {
        this._.push(
          "L", x0, ",", y0
        );
      }

      // Is this arc empty? We’re done.
      if (!r) return;

      // Is this a complete circle? Draw two arcs to complete the circle.
      if (da > tauEpsilon) {
        this._.push(
          "A", r, ",", r, ",0,1,", cw, ",", x - dx, ",", y - dy,
          "A", r, ",", r, ",0,1,", cw, ",", this._x1 = x0, ",", this._y1 = y0
        );
      }

      // Otherwise, draw an arc!
      else {
        if (da < 0) da = da % tau$1 + tau$1;
        this._.push(
          "A", r, ",", r, ",0,", +(da >= pi$1), ",", cw, ",", this._x1 = x + r * Math.cos(a1), ",", this._y1 = y + r * Math.sin(a1)
        );
      }
    },
    rect: function(x, y, w, h) {
      this._.push("M", this._x0 = this._x1 = +x, ",", this._y0 = this._y1 = +y, "h", +w, "v", +h, "h", -w, "Z");
    },
    toString: function() {
      return this._.join("");
    }
  };

  function tree_add(d) {
    var x = +this._x.call(null, d),
        y = +this._y.call(null, d);
    return add(this.cover(x, y), x, y, d);
  }

  function add(tree, x, y, d) {
    if (isNaN(x) || isNaN(y)) return tree; // ignore invalid points

    var parent,
        node = tree._root,
        leaf = {data: d},
        x0 = tree._x0,
        y0 = tree._y0,
        x1 = tree._x1,
        y1 = tree._y1,
        xm,
        ym,
        xp,
        yp,
        right,
        bottom,
        i,
        j;

    // If the tree is empty, initialize the root as a leaf.
    if (!node) return tree._root = leaf, tree;

    // Find the existing leaf for the new point, or add it.
    while (node.length) {
      if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
      if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
      if (parent = node, !(node = node[i = bottom << 1 | right])) return parent[i] = leaf, tree;
    }

    // Is the new point is exactly coincident with the existing point?
    xp = +tree._x.call(null, node.data);
    yp = +tree._y.call(null, node.data);
    if (x === xp && y === yp) return leaf.next = node, parent ? parent[i] = leaf : tree._root = leaf, tree;

    // Otherwise, split the leaf node until the old and new point are separated.
    do {
      parent = parent ? parent[i] = new Array(4) : tree._root = new Array(4);
      if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
      if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
    } while ((i = bottom << 1 | right) === (j = (yp >= ym) << 1 | (xp >= xm)));
    return parent[j] = node, parent[i] = leaf, tree;
  }

  function addAll(data) {
    var d, i, n = data.length,
        x,
        y,
        xz = new Array(n),
        yz = new Array(n),
        x0 = Infinity,
        y0 = Infinity,
        x1 = -Infinity,
        y1 = -Infinity;

    // Compute the points and their extent.
    for (i = 0; i < n; ++i) {
      if (isNaN(x = +this._x.call(null, d = data[i])) || isNaN(y = +this._y.call(null, d))) continue;
      xz[i] = x;
      yz[i] = y;
      if (x < x0) x0 = x;
      if (x > x1) x1 = x;
      if (y < y0) y0 = y;
      if (y > y1) y1 = y;
    }

    // If there were no (valid) points, inherit the existing extent.
    if (x1 < x0) x0 = this._x0, x1 = this._x1;
    if (y1 < y0) y0 = this._y0, y1 = this._y1;

    // Expand the tree to cover the new points.
    this.cover(x0, y0).cover(x1, y1);

    // Add the new points.
    for (i = 0; i < n; ++i) {
      add(this, xz[i], yz[i], data[i]);
    }

    return this;
  }

  function tree_cover(x, y) {
    if (isNaN(x = +x) || isNaN(y = +y)) return this; // ignore invalid points

    var x0 = this._x0,
        y0 = this._y0,
        x1 = this._x1,
        y1 = this._y1;

    // If the quadtree has no extent, initialize them.
    // Integer extent are necessary so that if we later double the extent,
    // the existing quadrant boundaries don’t change due to floating point error!
    if (isNaN(x0)) {
      x1 = (x0 = Math.floor(x)) + 1;
      y1 = (y0 = Math.floor(y)) + 1;
    }

    // Otherwise, double repeatedly to cover.
    else if (x0 > x || x > x1 || y0 > y || y > y1) {
      var z = x1 - x0,
          node = this._root,
          parent,
          i;

      switch (i = (y < (y0 + y1) / 2) << 1 | (x < (x0 + x1) / 2)) {
        case 0: {
          do parent = new Array(4), parent[i] = node, node = parent;
          while (z *= 2, x1 = x0 + z, y1 = y0 + z, x > x1 || y > y1);
          break;
        }
        case 1: {
          do parent = new Array(4), parent[i] = node, node = parent;
          while (z *= 2, x0 = x1 - z, y1 = y0 + z, x0 > x || y > y1);
          break;
        }
        case 2: {
          do parent = new Array(4), parent[i] = node, node = parent;
          while (z *= 2, x1 = x0 + z, y0 = y1 - z, x > x1 || y0 > y);
          break;
        }
        case 3: {
          do parent = new Array(4), parent[i] = node, node = parent;
          while (z *= 2, x0 = x1 - z, y0 = y1 - z, x0 > x || y0 > y);
          break;
        }
      }

      if (this._root && this._root.length) this._root = node;
    }

    // If the quadtree covers the point already, just return.
    else return this;

    this._x0 = x0;
    this._y0 = y0;
    this._x1 = x1;
    this._y1 = y1;
    return this;
  }

  function tree_data() {
    var data = [];
    this.visit(function(node) {
      if (!node.length) do data.push(node.data); while (node = node.next)
    });
    return data;
  }

  function tree_extent(_) {
    return arguments.length
        ? this.cover(+_[0][0], +_[0][1]).cover(+_[1][0], +_[1][1])
        : isNaN(this._x0) ? undefined : [[this._x0, this._y0], [this._x1, this._y1]];
  }

  function Quad(node, x0, y0, x1, y1) {
    this.node = node;
    this.x0 = x0;
    this.y0 = y0;
    this.x1 = x1;
    this.y1 = y1;
  }

  function tree_find(x, y, radius) {
    var data,
        x0 = this._x0,
        y0 = this._y0,
        x1,
        y1,
        x2,
        y2,
        x3 = this._x1,
        y3 = this._y1,
        quads = [],
        node = this._root,
        q,
        i;

    if (node) quads.push(new Quad(node, x0, y0, x3, y3));
    if (radius == null) radius = Infinity;
    else {
      x0 = x - radius, y0 = y - radius;
      x3 = x + radius, y3 = y + radius;
      radius *= radius;
    }

    while (q = quads.pop()) {

      // Stop searching if this quadrant can’t contain a closer node.
      if (!(node = q.node)
          || (x1 = q.x0) > x3
          || (y1 = q.y0) > y3
          || (x2 = q.x1) < x0
          || (y2 = q.y1) < y0) continue;

      // Bisect the current quadrant.
      if (node.length) {
        var xm = (x1 + x2) / 2,
            ym = (y1 + y2) / 2;

        quads.push(
          new Quad(node[3], xm, ym, x2, y2),
          new Quad(node[2], x1, ym, xm, y2),
          new Quad(node[1], xm, y1, x2, ym),
          new Quad(node[0], x1, y1, xm, ym)
        );

        // Visit the closest quadrant first.
        if (i = (y >= ym) << 1 | (x >= xm)) {
          q = quads[quads.length - 1];
          quads[quads.length - 1] = quads[quads.length - 1 - i];
          quads[quads.length - 1 - i] = q;
        }
      }

      // Visit this point. (Visiting coincident points isn’t necessary!)
      else {
        var dx = x - +this._x.call(null, node.data),
            dy = y - +this._y.call(null, node.data),
            d2 = dx * dx + dy * dy;
        if (d2 < radius) {
          var d = Math.sqrt(radius = d2);
          x0 = x - d, y0 = y - d;
          x3 = x + d, y3 = y + d;
          data = node.data;
        }
      }
    }

    return data;
  }

  function tree_remove(d) {
    if (isNaN(x = +this._x.call(null, d)) || isNaN(y = +this._y.call(null, d))) return this; // ignore invalid points

    var parent,
        node = this._root,
        retainer,
        previous,
        next,
        x0 = this._x0,
        y0 = this._y0,
        x1 = this._x1,
        y1 = this._y1,
        x,
        y,
        xm,
        ym,
        right,
        bottom,
        i,
        j;

    // If the tree is empty, initialize the root as a leaf.
    if (!node) return this;

    // Find the leaf node for the point.
    // While descending, also retain the deepest parent with a non-removed sibling.
    if (node.length) while (true) {
      if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
      if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
      if (!(parent = node, node = node[i = bottom << 1 | right])) return this;
      if (!node.length) break;
      if (parent[(i + 1) & 3] || parent[(i + 2) & 3] || parent[(i + 3) & 3]) retainer = parent, j = i;
    }

    // Find the point to remove.
    while (node.data !== d) if (!(previous = node, node = node.next)) return this;
    if (next = node.next) delete node.next;

    // If there are multiple coincident points, remove just the point.
    if (previous) return (next ? previous.next = next : delete previous.next), this;

    // If this is the root point, remove it.
    if (!parent) return this._root = next, this;

    // Remove this leaf.
    next ? parent[i] = next : delete parent[i];

    // If the parent now contains exactly one leaf, collapse superfluous parents.
    if ((node = parent[0] || parent[1] || parent[2] || parent[3])
        && node === (parent[3] || parent[2] || parent[1] || parent[0])
        && !node.length) {
      if (retainer) retainer[j] = node;
      else this._root = node;
    }

    return this;
  }

  function removeAll(data) {
    for (var i = 0, n = data.length; i < n; ++i) this.remove(data[i]);
    return this;
  }

  function tree_root() {
    return this._root;
  }

  function tree_size() {
    var size = 0;
    this.visit(function(node) {
      if (!node.length) do ++size; while (node = node.next)
    });
    return size;
  }

  function tree_visit(callback) {
    var quads = [], q, node = this._root, child, x0, y0, x1, y1;
    if (node) quads.push(new Quad(node, this._x0, this._y0, this._x1, this._y1));
    while (q = quads.pop()) {
      if (!callback(node = q.node, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1) && node.length) {
        var xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
        if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
        if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
        if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
        if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
      }
    }
    return this;
  }

  function tree_visitAfter(callback) {
    var quads = [], next = [], q;
    if (this._root) quads.push(new Quad(this._root, this._x0, this._y0, this._x1, this._y1));
    while (q = quads.pop()) {
      var node = q.node;
      if (node.length) {
        var child, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1, xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
        if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
        if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
        if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
        if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
      }
      next.push(q);
    }
    while (q = next.pop()) {
      callback(q.node, q.x0, q.y0, q.x1, q.y1);
    }
    return this;
  }

  function defaultX(d) {
    return d[0];
  }

  function tree_x(_) {
    return arguments.length ? (this._x = _, this) : this._x;
  }

  function defaultY(d) {
    return d[1];
  }

  function tree_y(_) {
    return arguments.length ? (this._y = _, this) : this._y;
  }

  function quadtree(nodes, x, y) {
    var tree = new Quadtree(x == null ? defaultX : x, y == null ? defaultY : y, NaN, NaN, NaN, NaN);
    return nodes == null ? tree : tree.addAll(nodes);
  }

  function Quadtree(x, y, x0, y0, x1, y1) {
    this._x = x;
    this._y = y;
    this._x0 = x0;
    this._y0 = y0;
    this._x1 = x1;
    this._y1 = y1;
    this._root = undefined;
  }

  function leaf_copy(leaf) {
    var copy = {data: leaf.data}, next = copy;
    while (leaf = leaf.next) next = next.next = {data: leaf.data};
    return copy;
  }

  var treeProto = quadtree.prototype = Quadtree.prototype;

  treeProto.copy = function() {
    var copy = new Quadtree(this._x, this._y, this._x0, this._y0, this._x1, this._y1),
        node = this._root,
        nodes,
        child;

    if (!node) return copy;

    if (!node.length) return copy._root = leaf_copy(node), copy;

    nodes = [{source: node, target: copy._root = new Array(4)}];
    while (node = nodes.pop()) {
      for (var i = 0; i < 4; ++i) {
        if (child = node.source[i]) {
          if (child.length) nodes.push({source: child, target: node.target[i] = new Array(4)});
          else node.target[i] = leaf_copy(child);
        }
      }
    }

    return copy;
  };

  treeProto.add = tree_add;
  treeProto.addAll = addAll;
  treeProto.cover = tree_cover;
  treeProto.data = tree_data;
  treeProto.extent = tree_extent;
  treeProto.find = tree_find;
  treeProto.remove = tree_remove;
  treeProto.removeAll = removeAll;
  treeProto.root = tree_root;
  treeProto.size = tree_size;
  treeProto.visit = tree_visit;
  treeProto.visitAfter = tree_visitAfter;
  treeProto.x = tree_x;
  treeProto.y = tree_y;

  var slice$1 = [].slice;

  var noabort = {};

  function Queue(size) {
    if (!(size >= 1)) throw new Error;
    this._size = size;
    this._call =
    this._error = null;
    this._tasks = [];
    this._data = [];
    this._waiting =
    this._active =
    this._ended =
    this._start = 0; // inside a synchronous task callback?
  }

  Queue.prototype = queue.prototype = {
    constructor: Queue,
    defer: function(callback) {
      if (typeof callback !== "function" || this._call) throw new Error;
      if (this._error != null) return this;
      var t = slice$1.call(arguments, 1);
      t.push(callback);
      ++this._waiting, this._tasks.push(t);
      poke(this);
      return this;
    },
    abort: function() {
      if (this._error == null) abort(this, new Error("abort"));
      return this;
    },
    await: function(callback) {
      if (typeof callback !== "function" || this._call) throw new Error;
      this._call = function(error, results) { callback.apply(null, [error].concat(results)); };
      maybeNotify(this);
      return this;
    },
    awaitAll: function(callback) {
      if (typeof callback !== "function" || this._call) throw new Error;
      this._call = callback;
      maybeNotify(this);
      return this;
    }
  };

  function poke(q) {
    if (!q._start) {
      try { start(q); } // let the current task complete
      catch (e) {
        if (q._tasks[q._ended + q._active - 1]) abort(q, e); // task errored synchronously
        else if (!q._data) throw e; // await callback errored synchronously
      }
    }
  }

  function start(q) {
    while (q._start = q._waiting && q._active < q._size) {
      var i = q._ended + q._active,
          t = q._tasks[i],
          j = t.length - 1,
          c = t[j];
      t[j] = end(q, i);
      --q._waiting, ++q._active;
      t = c.apply(null, t);
      if (!q._tasks[i]) continue; // task finished synchronously
      q._tasks[i] = t || noabort;
    }
  }

  function end(q, i) {
    return function(e, r) {
      if (!q._tasks[i]) return; // ignore multiple callbacks
      --q._active, ++q._ended;
      q._tasks[i] = null;
      if (q._error != null) return; // ignore secondary errors
      if (e != null) {
        abort(q, e);
      } else {
        q._data[i] = r;
        if (q._waiting) poke(q);
        else maybeNotify(q);
      }
    };
  }

  function abort(q, e) {
    var i = q._tasks.length, t;
    q._error = e; // ignore active callbacks
    q._data = undefined; // allow gc
    q._waiting = NaN; // prevent starting

    while (--i >= 0) {
      if (t = q._tasks[i]) {
        q._tasks[i] = null;
        if (t.abort) {
          try { t.abort(); }
          catch (e) { /* ignore */ }
        }
      }
    }

    q._active = NaN; // allow notification
    maybeNotify(q);
  }

  function maybeNotify(q) {
    if (!q._active && q._call) {
      var d = q._data;
      q._data = undefined; // allow gc
      q._call(q._error, d);
    }
  }

  function queue(concurrency) {
    return new Queue(arguments.length ? +concurrency : Infinity);
  }

  function constant$1(x) {
    return function constant() {
      return x;
    };
  }

  var epsilon$1 = 1e-12;
  var pi$2 = Math.PI;
  var halfPi$1 = pi$2 / 2;
  var tau$2 = 2 * pi$2;

  function arcInnerRadius(d) {
    return d.innerRadius;
  }

  function arcOuterRadius(d) {
    return d.outerRadius;
  }

  function arcStartAngle(d) {
    return d.startAngle;
  }

  function arcEndAngle(d) {
    return d.endAngle;
  }

  function arcPadAngle(d) {
    return d && d.padAngle; // Note: optional!
  }

  function asin(x) {
    return x >= 1 ? halfPi$1 : x <= -1 ? -halfPi$1 : Math.asin(x);
  }

  function intersect(x0, y0, x1, y1, x2, y2, x3, y3) {
    var x10 = x1 - x0, y10 = y1 - y0,
        x32 = x3 - x2, y32 = y3 - y2,
        t = (x32 * (y0 - y2) - y32 * (x0 - x2)) / (y32 * x10 - x32 * y10);
    return [x0 + t * x10, y0 + t * y10];
  }

  // Compute perpendicular offset line of length rc.
  // http://mathworld.wolfram.com/Circle-LineIntersection.html
  function cornerTangents(x0, y0, x1, y1, r1, rc, cw) {
    var x01 = x0 - x1,
        y01 = y0 - y1,
        lo = (cw ? rc : -rc) / Math.sqrt(x01 * x01 + y01 * y01),
        ox = lo * y01,
        oy = -lo * x01,
        x11 = x0 + ox,
        y11 = y0 + oy,
        x10 = x1 + ox,
        y10 = y1 + oy,
        x00 = (x11 + x10) / 2,
        y00 = (y11 + y10) / 2,
        dx = x10 - x11,
        dy = y10 - y11,
        d2 = dx * dx + dy * dy,
        r = r1 - rc,
        D = x11 * y10 - x10 * y11,
        d = (dy < 0 ? -1 : 1) * Math.sqrt(Math.max(0, r * r * d2 - D * D)),
        cx0 = (D * dy - dx * d) / d2,
        cy0 = (-D * dx - dy * d) / d2,
        cx1 = (D * dy + dx * d) / d2,
        cy1 = (-D * dx + dy * d) / d2,
        dx0 = cx0 - x00,
        dy0 = cy0 - y00,
        dx1 = cx1 - x00,
        dy1 = cy1 - y00;

    // Pick the closer of the two intersection points.
    // TODO Is there a faster way to determine which intersection to use?
    if (dx0 * dx0 + dy0 * dy0 > dx1 * dx1 + dy1 * dy1) cx0 = cx1, cy0 = cy1;

    return {
      cx: cx0,
      cy: cy0,
      x01: -ox,
      y01: -oy,
      x11: cx0 * (r1 / r - 1),
      y11: cy0 * (r1 / r - 1)
    };
  }

  function arc() {
    var innerRadius = arcInnerRadius,
        outerRadius = arcOuterRadius,
        cornerRadius = constant$1(0),
        padRadius = null,
        startAngle = arcStartAngle,
        endAngle = arcEndAngle,
        padAngle = arcPadAngle,
        context = null;

    function arc() {
      var buffer,
          r,
          r0 = +innerRadius.apply(this, arguments),
          r1 = +outerRadius.apply(this, arguments),
          a0 = startAngle.apply(this, arguments) - halfPi$1,
          a1 = endAngle.apply(this, arguments) - halfPi$1,
          da = Math.abs(a1 - a0),
          cw = a1 > a0;

      if (!context) context = buffer = path();

      // Ensure that the outer radius is always larger than the inner radius.
      if (r1 < r0) r = r1, r1 = r0, r0 = r;

      // Is it a point?
      if (!(r1 > epsilon$1)) context.moveTo(0, 0);

      // Or is it a circle or annulus?
      else if (da > tau$2 - epsilon$1) {
        context.moveTo(r1 * Math.cos(a0), r1 * Math.sin(a0));
        context.arc(0, 0, r1, a0, a1, !cw);
        if (r0 > epsilon$1) {
          context.moveTo(r0 * Math.cos(a1), r0 * Math.sin(a1));
          context.arc(0, 0, r0, a1, a0, cw);
        }
      }

      // Or is it a circular or annular sector?
      else {
        var a01 = a0,
            a11 = a1,
            a00 = a0,
            a10 = a1,
            da0 = da,
            da1 = da,
            ap = padAngle.apply(this, arguments) / 2,
            rp = (ap > epsilon$1) && (padRadius ? +padRadius.apply(this, arguments) : Math.sqrt(r0 * r0 + r1 * r1)),
            rc = Math.min(Math.abs(r1 - r0) / 2, +cornerRadius.apply(this, arguments)),
            rc0 = rc,
            rc1 = rc,
            t0,
            t1;

        // Apply padding? Note that since r1 ≥ r0, da1 ≥ da0.
        if (rp > epsilon$1) {
          var p0 = asin(rp / r0 * Math.sin(ap)),
              p1 = asin(rp / r1 * Math.sin(ap));
          if ((da0 -= p0 * 2) > epsilon$1) p0 *= (cw ? 1 : -1), a00 += p0, a10 -= p0;
          else da0 = 0, a00 = a10 = (a0 + a1) / 2;
          if ((da1 -= p1 * 2) > epsilon$1) p1 *= (cw ? 1 : -1), a01 += p1, a11 -= p1;
          else da1 = 0, a01 = a11 = (a0 + a1) / 2;
        }

        var x01 = r1 * Math.cos(a01),
            y01 = r1 * Math.sin(a01),
            x10 = r0 * Math.cos(a10),
            y10 = r0 * Math.sin(a10);

        // Apply rounded corners?
        if (rc > epsilon$1) {
          var x11 = r1 * Math.cos(a11),
              y11 = r1 * Math.sin(a11),
              x00 = r0 * Math.cos(a00),
              y00 = r0 * Math.sin(a00);

          // Restrict the corner radius according to the sector angle.
          if (da < pi$2) {
            var oc = da0 > epsilon$1 ? intersect(x01, y01, x00, y00, x11, y11, x10, y10) : [x10, y10],
                ax = x01 - oc[0],
                ay = y01 - oc[1],
                bx = x11 - oc[0],
                by = y11 - oc[1],
                kc = 1 / Math.sin(Math.acos((ax * bx + ay * by) / (Math.sqrt(ax * ax + ay * ay) * Math.sqrt(bx * bx + by * by))) / 2),
                lc = Math.sqrt(oc[0] * oc[0] + oc[1] * oc[1]);
            rc0 = Math.min(rc, (r0 - lc) / (kc - 1));
            rc1 = Math.min(rc, (r1 - lc) / (kc + 1));
          }
        }

        // Is the sector collapsed to a line?
        if (!(da1 > epsilon$1)) context.moveTo(x01, y01);

        // Does the sector’s outer ring have rounded corners?
        else if (rc1 > epsilon$1) {
          t0 = cornerTangents(x00, y00, x01, y01, r1, rc1, cw);
          t1 = cornerTangents(x11, y11, x10, y10, r1, rc1, cw);

          context.moveTo(t0.cx + t0.x01, t0.cy + t0.y01);

          // Have the corners merged?
          if (rc1 < rc) context.arc(t0.cx, t0.cy, rc1, Math.atan2(t0.y01, t0.x01), Math.atan2(t1.y01, t1.x01), !cw);

          // Otherwise, draw the two corners and the ring.
          else {
            context.arc(t0.cx, t0.cy, rc1, Math.atan2(t0.y01, t0.x01), Math.atan2(t0.y11, t0.x11), !cw);
            context.arc(0, 0, r1, Math.atan2(t0.cy + t0.y11, t0.cx + t0.x11), Math.atan2(t1.cy + t1.y11, t1.cx + t1.x11), !cw);
            context.arc(t1.cx, t1.cy, rc1, Math.atan2(t1.y11, t1.x11), Math.atan2(t1.y01, t1.x01), !cw);
          }
        }

        // Or is the outer ring just a circular arc?
        else context.moveTo(x01, y01), context.arc(0, 0, r1, a01, a11, !cw);

        // Is there no inner ring, and it’s a circular sector?
        // Or perhaps it’s an annular sector collapsed due to padding?
        if (!(r0 > epsilon$1) || !(da0 > epsilon$1)) context.lineTo(x10, y10);

        // Does the sector’s inner ring (or point) have rounded corners?
        else if (rc0 > epsilon$1) {
          t0 = cornerTangents(x10, y10, x11, y11, r0, -rc0, cw);
          t1 = cornerTangents(x01, y01, x00, y00, r0, -rc0, cw);

          context.lineTo(t0.cx + t0.x01, t0.cy + t0.y01);

          // Have the corners merged?
          if (rc0 < rc) context.arc(t0.cx, t0.cy, rc0, Math.atan2(t0.y01, t0.x01), Math.atan2(t1.y01, t1.x01), !cw);

          // Otherwise, draw the two corners and the ring.
          else {
            context.arc(t0.cx, t0.cy, rc0, Math.atan2(t0.y01, t0.x01), Math.atan2(t0.y11, t0.x11), !cw);
            context.arc(0, 0, r0, Math.atan2(t0.cy + t0.y11, t0.cx + t0.x11), Math.atan2(t1.cy + t1.y11, t1.cx + t1.x11), cw);
            context.arc(t1.cx, t1.cy, rc0, Math.atan2(t1.y11, t1.x11), Math.atan2(t1.y01, t1.x01), !cw);
          }
        }

        // Or is the inner ring just a circular arc?
        else context.arc(0, 0, r0, a10, a00, cw);
      }

      context.closePath();

      if (buffer) return context = null, buffer + "" || null;
    }

    arc.centroid = function() {
      var r = (+innerRadius.apply(this, arguments) + +outerRadius.apply(this, arguments)) / 2,
          a = (+startAngle.apply(this, arguments) + +endAngle.apply(this, arguments)) / 2 - pi$2 / 2;
      return [Math.cos(a) * r, Math.sin(a) * r];
    };

    arc.innerRadius = function(_) {
      return arguments.length ? (innerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : innerRadius;
    };

    arc.outerRadius = function(_) {
      return arguments.length ? (outerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : outerRadius;
    };

    arc.cornerRadius = function(_) {
      return arguments.length ? (cornerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : cornerRadius;
    };

    arc.padRadius = function(_) {
      return arguments.length ? (padRadius = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), arc) : padRadius;
    };

    arc.startAngle = function(_) {
      return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : startAngle;
    };

    arc.endAngle = function(_) {
      return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : endAngle;
    };

    arc.padAngle = function(_) {
      return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : padAngle;
    };

    arc.context = function(_) {
      return arguments.length ? ((context = _ == null ? null : _), arc) : context;
    };

    return arc;
  }

  function Linear(context) {
    this._context = context;
  }

  Linear.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._point = 0;
    },
    lineEnd: function() {
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; // proceed
        default: this._context.lineTo(x, y); break;
      }
    }
  };

  function curveLinear(context) {
    return new Linear(context);
  }

  function x(p) {
    return p[0];
  }

  function y(p) {
    return p[1];
  }

  function line() {
    var x$$ = x,
        y$$ = y,
        defined = constant$1(true),
        context = null,
        curve = curveLinear,
        output = null;

    function line(data) {
      var i,
          n = data.length,
          d,
          defined0 = false,
          buffer;

      if (context == null) output = curve(buffer = path());

      for (i = 0; i <= n; ++i) {
        if (!(i < n && defined(d = data[i], i, data)) === defined0) {
          if (defined0 = !defined0) output.lineStart();
          else output.lineEnd();
        }
        if (defined0) output.point(+x$$(d, i, data), +y$$(d, i, data));
      }

      if (buffer) return output = null, buffer + "" || null;
    }

    line.x = function(_) {
      return arguments.length ? (x$$ = typeof _ === "function" ? _ : constant$1(+_), line) : x$$;
    };

    line.y = function(_) {
      return arguments.length ? (y$$ = typeof _ === "function" ? _ : constant$1(+_), line) : y$$;
    };

    line.defined = function(_) {
      return arguments.length ? (defined = typeof _ === "function" ? _ : constant$1(!!_), line) : defined;
    };

    line.curve = function(_) {
      return arguments.length ? (curve = _, context != null && (output = curve(context)), line) : curve;
    };

    line.context = function(_) {
      return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), line) : context;
    };

    return line;
  }

  function area$1() {
    var x0 = x,
        x1 = null,
        y0 = constant$1(0),
        y1 = y,
        defined = constant$1(true),
        context = null,
        curve = curveLinear,
        output = null;

    function area(data) {
      var i,
          j,
          k,
          n = data.length,
          d,
          defined0 = false,
          buffer,
          x0z = new Array(n),
          y0z = new Array(n);

      if (context == null) output = curve(buffer = path());

      for (i = 0; i <= n; ++i) {
        if (!(i < n && defined(d = data[i], i, data)) === defined0) {
          if (defined0 = !defined0) {
            j = i;
            output.areaStart();
            output.lineStart();
          } else {
            output.lineEnd();
            output.lineStart();
            for (k = i - 1; k >= j; --k) {
              output.point(x0z[k], y0z[k]);
            }
            output.lineEnd();
            output.areaEnd();
          }
        }
        if (defined0) {
          x0z[i] = +x0(d, i, data), y0z[i] = +y0(d, i, data);
          output.point(x1 ? +x1(d, i, data) : x0z[i], y1 ? +y1(d, i, data) : y0z[i]);
        }
      }

      if (buffer) return output = null, buffer + "" || null;
    }

    function arealine() {
      return line().defined(defined).curve(curve).context(context);
    }

    area.x = function(_) {
      return arguments.length ? (x0 = typeof _ === "function" ? _ : constant$1(+_), x1 = null, area) : x0;
    };

    area.x0 = function(_) {
      return arguments.length ? (x0 = typeof _ === "function" ? _ : constant$1(+_), area) : x0;
    };

    area.x1 = function(_) {
      return arguments.length ? (x1 = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), area) : x1;
    };

    area.y = function(_) {
      return arguments.length ? (y0 = typeof _ === "function" ? _ : constant$1(+_), y1 = null, area) : y0;
    };

    area.y0 = function(_) {
      return arguments.length ? (y0 = typeof _ === "function" ? _ : constant$1(+_), area) : y0;
    };

    area.y1 = function(_) {
      return arguments.length ? (y1 = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), area) : y1;
    };

    area.lineX0 =
    area.lineY0 = function() {
      return arealine().x(x0).y(y0);
    };

    area.lineY1 = function() {
      return arealine().x(x0).y(y1);
    };

    area.lineX1 = function() {
      return arealine().x(x1).y(y0);
    };

    area.defined = function(_) {
      return arguments.length ? (defined = typeof _ === "function" ? _ : constant$1(!!_), area) : defined;
    };

    area.curve = function(_) {
      return arguments.length ? (curve = _, context != null && (output = curve(context)), area) : curve;
    };

    area.context = function(_) {
      return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), area) : context;
    };

    return area;
  }

  function descending$1(a, b) {
    return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
  }

  function identity$1(d) {
    return d;
  }

  function pie() {
    var value = identity$1,
        sortValues = descending$1,
        sort = null,
        startAngle = constant$1(0),
        endAngle = constant$1(tau$2),
        padAngle = constant$1(0);

    function pie(data) {
      var i,
          n = data.length,
          j,
          k,
          sum = 0,
          index = new Array(n),
          arcs = new Array(n),
          a0 = +startAngle.apply(this, arguments),
          da = Math.min(tau$2, Math.max(-tau$2, endAngle.apply(this, arguments) - a0)),
          a1,
          p = Math.min(Math.abs(da) / n, padAngle.apply(this, arguments)),
          pa = p * (da < 0 ? -1 : 1),
          v;

      for (i = 0; i < n; ++i) {
        if ((v = arcs[index[i] = i] = +value(data[i], i, data)) > 0) {
          sum += v;
        }
      }

      // Optionally sort the arcs by previously-computed values or by data.
      if (sortValues != null) index.sort(function(i, j) { return sortValues(arcs[i], arcs[j]); });
      else if (sort != null) index.sort(function(i, j) { return sort(data[i], data[j]); });

      // Compute the arcs! They are stored in the original data's order.
      for (i = 0, k = sum ? (da - n * pa) / sum : 0; i < n; ++i, a0 = a1) {
        j = index[i], v = arcs[j], a1 = a0 + (v > 0 ? v * k : 0) + pa, arcs[j] = {
          data: data[j],
          index: i,
          value: v,
          startAngle: a0,
          endAngle: a1,
          padAngle: p
        };
      }

      return arcs;
    }

    pie.value = function(_) {
      return arguments.length ? (value = typeof _ === "function" ? _ : constant$1(+_), pie) : value;
    };

    pie.sortValues = function(_) {
      return arguments.length ? (sortValues = _, sort = null, pie) : sortValues;
    };

    pie.sort = function(_) {
      return arguments.length ? (sort = _, sortValues = null, pie) : sort;
    };

    pie.startAngle = function(_) {
      return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : startAngle;
    };

    pie.endAngle = function(_) {
      return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : endAngle;
    };

    pie.padAngle = function(_) {
      return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : padAngle;
    };

    return pie;
  }

  var curveRadialLinear = curveRadial(curveLinear);

  function Radial(curve) {
    this._curve = curve;
  }

  Radial.prototype = {
    areaStart: function() {
      this._curve.areaStart();
    },
    areaEnd: function() {
      this._curve.areaEnd();
    },
    lineStart: function() {
      this._curve.lineStart();
    },
    lineEnd: function() {
      this._curve.lineEnd();
    },
    point: function(a, r) {
      this._curve.point(r * Math.sin(a), r * -Math.cos(a));
    }
  };

  function curveRadial(curve) {

    function radial(context) {
      return new Radial(curve(context));
    }

    radial._curve = curve;

    return radial;
  }

  function radialLine(l) {
    var c = l.curve;

    l.angle = l.x, delete l.x;
    l.radius = l.y, delete l.y;

    l.curve = function(_) {
      return arguments.length ? c(curveRadial(_)) : c()._curve;
    };

    return l;
  }

  function radialLine$1() {
    return radialLine(line().curve(curveRadialLinear));
  }

  function radialArea() {
    var a = area$1().curve(curveRadialLinear),
        c = a.curve,
        x0 = a.lineX0,
        x1 = a.lineX1,
        y0 = a.lineY0,
        y1 = a.lineY1;

    a.angle = a.x, delete a.x;
    a.startAngle = a.x0, delete a.x0;
    a.endAngle = a.x1, delete a.x1;
    a.radius = a.y, delete a.y;
    a.innerRadius = a.y0, delete a.y0;
    a.outerRadius = a.y1, delete a.y1;
    a.lineStartAngle = function() { return radialLine(x0()); }, delete a.lineX0;
    a.lineEndAngle = function() { return radialLine(x1()); }, delete a.lineX1;
    a.lineInnerRadius = function() { return radialLine(y0()); }, delete a.lineY0;
    a.lineOuterRadius = function() { return radialLine(y1()); }, delete a.lineY1;

    a.curve = function(_) {
      return arguments.length ? c(curveRadial(_)) : c()._curve;
    };

    return a;
  }

  var circle = {
    draw: function(context, size) {
      var r = Math.sqrt(size / pi$2);
      context.moveTo(r, 0);
      context.arc(0, 0, r, 0, tau$2);
    }
  };

  var cross$1 = {
    draw: function(context, size) {
      var r = Math.sqrt(size / 5) / 2;
      context.moveTo(-3 * r, -r);
      context.lineTo(-r, -r);
      context.lineTo(-r, -3 * r);
      context.lineTo(r, -3 * r);
      context.lineTo(r, -r);
      context.lineTo(3 * r, -r);
      context.lineTo(3 * r, r);
      context.lineTo(r, r);
      context.lineTo(r, 3 * r);
      context.lineTo(-r, 3 * r);
      context.lineTo(-r, r);
      context.lineTo(-3 * r, r);
      context.closePath();
    }
  };

  var tan30 = Math.sqrt(1 / 3);
  var tan30_2 = tan30 * 2;
  var diamond = {
    draw: function(context, size) {
      var y = Math.sqrt(size / tan30_2),
          x = y * tan30;
      context.moveTo(0, -y);
      context.lineTo(x, 0);
      context.lineTo(0, y);
      context.lineTo(-x, 0);
      context.closePath();
    }
  };

  var ka = 0.89081309152928522810;
  var kr = Math.sin(pi$2 / 10) / Math.sin(7 * pi$2 / 10);
  var kx = Math.sin(tau$2 / 10) * kr;
  var ky = -Math.cos(tau$2 / 10) * kr;
  var star = {
    draw: function(context, size) {
      var r = Math.sqrt(size * ka),
          x = kx * r,
          y = ky * r;
      context.moveTo(0, -r);
      context.lineTo(x, y);
      for (var i = 1; i < 5; ++i) {
        var a = tau$2 * i / 5,
            c = Math.cos(a),
            s = Math.sin(a);
        context.lineTo(s * r, -c * r);
        context.lineTo(c * x - s * y, s * x + c * y);
      }
      context.closePath();
    }
  };

  var square = {
    draw: function(context, size) {
      var w = Math.sqrt(size),
          x = -w / 2;
      context.rect(x, x, w, w);
    }
  };

  var sqrt3 = Math.sqrt(3);

  var triangle = {
    draw: function(context, size) {
      var y = -Math.sqrt(size / (sqrt3 * 3));
      context.moveTo(0, y * 2);
      context.lineTo(-sqrt3 * y, -y);
      context.lineTo(sqrt3 * y, -y);
      context.closePath();
    }
  };

  var c = -0.5;
  var s = Math.sqrt(3) / 2;
  var k = 1 / Math.sqrt(12);
  var a = (k / 2 + 1) * 3;
  var wye = {
    draw: function(context, size) {
      var r = Math.sqrt(size / a),
          x0 = r / 2,
          y0 = r * k,
          x1 = x0,
          y1 = r * k + r,
          x2 = -x1,
          y2 = y1;
      context.moveTo(x0, y0);
      context.lineTo(x1, y1);
      context.lineTo(x2, y2);
      context.lineTo(c * x0 - s * y0, s * x0 + c * y0);
      context.lineTo(c * x1 - s * y1, s * x1 + c * y1);
      context.lineTo(c * x2 - s * y2, s * x2 + c * y2);
      context.lineTo(c * x0 + s * y0, c * y0 - s * x0);
      context.lineTo(c * x1 + s * y1, c * y1 - s * x1);
      context.lineTo(c * x2 + s * y2, c * y2 - s * x2);
      context.closePath();
    }
  };

  var symbols = [
    circle,
    cross$1,
    diamond,
    square,
    star,
    triangle,
    wye
  ];

  function symbol() {
    var type = constant$1(circle),
        size = constant$1(64),
        context = null;

    function symbol() {
      var buffer;
      if (!context) context = buffer = path();
      type.apply(this, arguments).draw(context, +size.apply(this, arguments));
      if (buffer) return context = null, buffer + "" || null;
    }

    symbol.type = function(_) {
      return arguments.length ? (type = typeof _ === "function" ? _ : constant$1(_), symbol) : type;
    };

    symbol.size = function(_) {
      return arguments.length ? (size = typeof _ === "function" ? _ : constant$1(+_), symbol) : size;
    };

    symbol.context = function(_) {
      return arguments.length ? (context = _ == null ? null : _, symbol) : context;
    };

    return symbol;
  }

  function noop() {}

  function point(that, x, y) {
    that._context.bezierCurveTo(
      (2 * that._x0 + that._x1) / 3,
      (2 * that._y0 + that._y1) / 3,
      (that._x0 + 2 * that._x1) / 3,
      (that._y0 + 2 * that._y1) / 3,
      (that._x0 + 4 * that._x1 + x) / 6,
      (that._y0 + 4 * that._y1 + y) / 6
    );
  }

  function Basis(context) {
    this._context = context;
  }

  Basis.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 =
      this._y0 = this._y1 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 3: point(this, this._x1, this._y1); // proceed
        case 2: this._context.lineTo(this._x1, this._y1); break;
      }
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; this._context.lineTo((5 * this._x0 + this._x1) / 6, (5 * this._y0 + this._y1) / 6); // proceed
        default: point(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = x;
      this._y0 = this._y1, this._y1 = y;
    }
  };

  function basis(context) {
    return new Basis(context);
  }

  function BasisClosed(context) {
    this._context = context;
  }

  BasisClosed.prototype = {
    areaStart: noop,
    areaEnd: noop,
    lineStart: function() {
      this._x0 = this._x1 = this._x2 = this._x3 = this._x4 =
      this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 1: {
          this._context.moveTo(this._x2, this._y2);
          this._context.closePath();
          break;
        }
        case 2: {
          this._context.moveTo((this._x2 + 2 * this._x3) / 3, (this._y2 + 2 * this._y3) / 3);
          this._context.lineTo((this._x3 + 2 * this._x2) / 3, (this._y3 + 2 * this._y2) / 3);
          this._context.closePath();
          break;
        }
        case 3: {
          this.point(this._x2, this._y2);
          this.point(this._x3, this._y3);
          this.point(this._x4, this._y4);
          break;
        }
      }
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._x2 = x, this._y2 = y; break;
        case 1: this._point = 2; this._x3 = x, this._y3 = y; break;
        case 2: this._point = 3; this._x4 = x, this._y4 = y; this._context.moveTo((this._x0 + 4 * this._x1 + x) / 6, (this._y0 + 4 * this._y1 + y) / 6); break;
        default: point(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = x;
      this._y0 = this._y1, this._y1 = y;
    }
  };

  function basisClosed(context) {
    return new BasisClosed(context);
  }

  function BasisOpen(context) {
    this._context = context;
  }

  BasisOpen.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 =
      this._y0 = this._y1 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; var x0 = (this._x0 + 4 * this._x1 + x) / 6, y0 = (this._y0 + 4 * this._y1 + y) / 6; this._line ? this._context.lineTo(x0, y0) : this._context.moveTo(x0, y0); break;
        case 3: this._point = 4; // proceed
        default: point(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = x;
      this._y0 = this._y1, this._y1 = y;
    }
  };

  function basisOpen(context) {
    return new BasisOpen(context);
  }

  function Bundle(context, beta) {
    this._basis = new Basis(context);
    this._beta = beta;
  }

  Bundle.prototype = {
    lineStart: function() {
      this._x = [];
      this._y = [];
      this._basis.lineStart();
    },
    lineEnd: function() {
      var x = this._x,
          y = this._y,
          j = x.length - 1;

      if (j > 0) {
        var x0 = x[0],
            y0 = y[0],
            dx = x[j] - x0,
            dy = y[j] - y0,
            i = -1,
            t;

        while (++i <= j) {
          t = i / j;
          this._basis.point(
            this._beta * x[i] + (1 - this._beta) * (x0 + t * dx),
            this._beta * y[i] + (1 - this._beta) * (y0 + t * dy)
          );
        }
      }

      this._x = this._y = null;
      this._basis.lineEnd();
    },
    point: function(x, y) {
      this._x.push(+x);
      this._y.push(+y);
    }
  };

  var bundle = (function custom(beta) {

    function bundle(context) {
      return beta === 1 ? new Basis(context) : new Bundle(context, beta);
    }

    bundle.beta = function(beta) {
      return custom(+beta);
    };

    return bundle;
  })(0.85);

  function point$1(that, x, y) {
    that._context.bezierCurveTo(
      that._x1 + that._k * (that._x2 - that._x0),
      that._y1 + that._k * (that._y2 - that._y0),
      that._x2 + that._k * (that._x1 - x),
      that._y2 + that._k * (that._y1 - y),
      that._x2,
      that._y2
    );
  }

  function Cardinal(context, tension) {
    this._context = context;
    this._k = (1 - tension) / 6;
  }

  Cardinal.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 = this._x2 =
      this._y0 = this._y1 = this._y2 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 2: this._context.lineTo(this._x2, this._y2); break;
        case 3: point$1(this, this._x1, this._y1); break;
      }
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; this._x1 = x, this._y1 = y; break;
        case 2: this._point = 3; // proceed
        default: point$1(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var cardinal = (function custom(tension) {

    function cardinal(context) {
      return new Cardinal(context, tension);
    }

    cardinal.tension = function(tension) {
      return custom(+tension);
    };

    return cardinal;
  })(0);

  function CardinalClosed(context, tension) {
    this._context = context;
    this._k = (1 - tension) / 6;
  }

  CardinalClosed.prototype = {
    areaStart: noop,
    areaEnd: noop,
    lineStart: function() {
      this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
      this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 1: {
          this._context.moveTo(this._x3, this._y3);
          this._context.closePath();
          break;
        }
        case 2: {
          this._context.lineTo(this._x3, this._y3);
          this._context.closePath();
          break;
        }
        case 3: {
          this.point(this._x3, this._y3);
          this.point(this._x4, this._y4);
          this.point(this._x5, this._y5);
          break;
        }
      }
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
        case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
        case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
        default: point$1(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var cardinalClosed = (function custom(tension) {

    function cardinal(context) {
      return new CardinalClosed(context, tension);
    }

    cardinal.tension = function(tension) {
      return custom(+tension);
    };

    return cardinal;
  })(0);

  function CardinalOpen(context, tension) {
    this._context = context;
    this._k = (1 - tension) / 6;
  }

  CardinalOpen.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 = this._x2 =
      this._y0 = this._y1 = this._y2 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
        case 3: this._point = 4; // proceed
        default: point$1(this, x, y); break;
      }
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var cardinalOpen = (function custom(tension) {

    function cardinal(context) {
      return new CardinalOpen(context, tension);
    }

    cardinal.tension = function(tension) {
      return custom(+tension);
    };

    return cardinal;
  })(0);

  function point$2(that, x, y) {
    var x1 = that._x1,
        y1 = that._y1,
        x2 = that._x2,
        y2 = that._y2;

    if (that._l01_a > epsilon$1) {
      var a = 2 * that._l01_2a + 3 * that._l01_a * that._l12_a + that._l12_2a,
          n = 3 * that._l01_a * (that._l01_a + that._l12_a);
      x1 = (x1 * a - that._x0 * that._l12_2a + that._x2 * that._l01_2a) / n;
      y1 = (y1 * a - that._y0 * that._l12_2a + that._y2 * that._l01_2a) / n;
    }

    if (that._l23_a > epsilon$1) {
      var b = 2 * that._l23_2a + 3 * that._l23_a * that._l12_a + that._l12_2a,
          m = 3 * that._l23_a * (that._l23_a + that._l12_a);
      x2 = (x2 * b + that._x1 * that._l23_2a - x * that._l12_2a) / m;
      y2 = (y2 * b + that._y1 * that._l23_2a - y * that._l12_2a) / m;
    }

    that._context.bezierCurveTo(x1, y1, x2, y2, that._x2, that._y2);
  }

  function CatmullRom(context, alpha) {
    this._context = context;
    this._alpha = alpha;
  }

  CatmullRom.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 = this._x2 =
      this._y0 = this._y1 = this._y2 = NaN;
      this._l01_a = this._l12_a = this._l23_a =
      this._l01_2a = this._l12_2a = this._l23_2a =
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 2: this._context.lineTo(this._x2, this._y2); break;
        case 3: this.point(this, this._x2, this._y2); break;
      }
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;

      if (this._point) {
        var x23 = this._x2 - x,
            y23 = this._y2 - y;
        this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
      }

      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; // proceed
        default: point$2(this, x, y); break;
      }

      this._l01_a = this._l12_a, this._l12_a = this._l23_a;
      this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var catmullRom = (function custom(alpha) {

    function catmullRom(context) {
      return alpha ? new CatmullRom(context, alpha) : new Cardinal(context, 0);
    }

    catmullRom.alpha = function(alpha) {
      return custom(+alpha);
    };

    return catmullRom;
  })(0.5);

  function CatmullRomClosed(context, alpha) {
    this._context = context;
    this._alpha = alpha;
  }

  CatmullRomClosed.prototype = {
    areaStart: noop,
    areaEnd: noop,
    lineStart: function() {
      this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
      this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
      this._l01_a = this._l12_a = this._l23_a =
      this._l01_2a = this._l12_2a = this._l23_2a =
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 1: {
          this._context.moveTo(this._x3, this._y3);
          this._context.closePath();
          break;
        }
        case 2: {
          this._context.lineTo(this._x3, this._y3);
          this._context.closePath();
          break;
        }
        case 3: {
          this.point(this._x3, this._y3);
          this.point(this._x4, this._y4);
          this.point(this._x5, this._y5);
          break;
        }
      }
    },
    point: function(x, y) {
      x = +x, y = +y;

      if (this._point) {
        var x23 = this._x2 - x,
            y23 = this._y2 - y;
        this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
      }

      switch (this._point) {
        case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
        case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
        case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
        default: point$2(this, x, y); break;
      }

      this._l01_a = this._l12_a, this._l12_a = this._l23_a;
      this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var catmullRomClosed = (function custom(alpha) {

    function catmullRom(context) {
      return alpha ? new CatmullRomClosed(context, alpha) : new CardinalClosed(context, 0);
    }

    catmullRom.alpha = function(alpha) {
      return custom(+alpha);
    };

    return catmullRom;
  })(0.5);

  function CatmullRomOpen(context, alpha) {
    this._context = context;
    this._alpha = alpha;
  }

  CatmullRomOpen.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 = this._x2 =
      this._y0 = this._y1 = this._y2 = NaN;
      this._l01_a = this._l12_a = this._l23_a =
      this._l01_2a = this._l12_2a = this._l23_2a =
      this._point = 0;
    },
    lineEnd: function() {
      if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;

      if (this._point) {
        var x23 = this._x2 - x,
            y23 = this._y2 - y;
        this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
      }

      switch (this._point) {
        case 0: this._point = 1; break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
        case 3: this._point = 4; // proceed
        default: point$2(this, x, y); break;
      }

      this._l01_a = this._l12_a, this._l12_a = this._l23_a;
      this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
      this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
      this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
    }
  };

  var catmullRomOpen = (function custom(alpha) {

    function catmullRom(context) {
      return alpha ? new CatmullRomOpen(context, alpha) : new CardinalOpen(context, 0);
    }

    catmullRom.alpha = function(alpha) {
      return custom(+alpha);
    };

    return catmullRom;
  })(0.5);

  function LinearClosed(context) {
    this._context = context;
  }

  LinearClosed.prototype = {
    areaStart: noop,
    areaEnd: noop,
    lineStart: function() {
      this._point = 0;
    },
    lineEnd: function() {
      if (this._point) this._context.closePath();
    },
    point: function(x, y) {
      x = +x, y = +y;
      if (this._point) this._context.lineTo(x, y);
      else this._point = 1, this._context.moveTo(x, y);
    }
  };

  function linearClosed(context) {
    return new LinearClosed(context);
  }

  function sign(x) {
    return x < 0 ? -1 : 1;
  }

  // Calculate the slopes of the tangents (Hermite-type interpolation) based on
  // the following paper: Steffen, M. 1990. A Simple Method for Monotonic
  // Interpolation in One Dimension. Astronomy and Astrophysics, Vol. 239, NO.
  // NOV(II), P. 443, 1990.
  function slope3(that, x2, y2) {
    var h0 = that._x1 - that._x0,
        h1 = x2 - that._x1,
        s0 = (that._y1 - that._y0) / (h0 || h1 < 0 && -0),
        s1 = (y2 - that._y1) / (h1 || h0 < 0 && -0),
        p = (s0 * h1 + s1 * h0) / (h0 + h1);
    return (sign(s0) + sign(s1)) * Math.min(Math.abs(s0), Math.abs(s1), 0.5 * Math.abs(p)) || 0;
  }

  // Calculate a one-sided slope.
  function slope2(that, t) {
    var h = that._x1 - that._x0;
    return h ? (3 * (that._y1 - that._y0) / h - t) / 2 : t;
  }

  // According to https://en.wikipedia.org/wiki/Cubic_Hermite_spline#Representations
  // "you can express cubic Hermite interpolation in terms of cubic Bézier curves
  // with respect to the four values p0, p0 + m0 / 3, p1 - m1 / 3, p1".
  function point$3(that, t0, t1) {
    var x0 = that._x0,
        y0 = that._y0,
        x1 = that._x1,
        y1 = that._y1,
        dx = (x1 - x0) / 3;
    that._context.bezierCurveTo(x0 + dx, y0 + dx * t0, x1 - dx, y1 - dx * t1, x1, y1);
  }

  function MonotoneX(context) {
    this._context = context;
  }

  MonotoneX.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x0 = this._x1 =
      this._y0 = this._y1 =
      this._t0 = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      switch (this._point) {
        case 2: this._context.lineTo(this._x1, this._y1); break;
        case 3: point$3(this, this._t0, slope2(this, this._t0)); break;
      }
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      this._line = 1 - this._line;
    },
    point: function(x, y) {
      var t1 = NaN;

      x = +x, y = +y;
      if (x === this._x1 && y === this._y1) return; // Ignore coincident points.
      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; break;
        case 2: this._point = 3; point$3(this, slope2(this, t1 = slope3(this, x, y)), t1); break;
        default: point$3(this, this._t0, t1 = slope3(this, x, y)); break;
      }

      this._x0 = this._x1, this._x1 = x;
      this._y0 = this._y1, this._y1 = y;
      this._t0 = t1;
    }
  }

  function MonotoneY(context) {
    this._context = new ReflectContext(context);
  }

  (MonotoneY.prototype = Object.create(MonotoneX.prototype)).point = function(x, y) {
    MonotoneX.prototype.point.call(this, y, x);
  };

  function ReflectContext(context) {
    this._context = context;
  }

  ReflectContext.prototype = {
    moveTo: function(x, y) { this._context.moveTo(y, x); },
    closePath: function() { this._context.closePath(); },
    lineTo: function(x, y) { this._context.lineTo(y, x); },
    bezierCurveTo: function(x1, y1, x2, y2, x, y) { this._context.bezierCurveTo(y1, x1, y2, x2, y, x); }
  };

  function monotoneX(context) {
    return new MonotoneX(context);
  }

  function monotoneY(context) {
    return new MonotoneY(context);
  }

  function Natural(context) {
    this._context = context;
  }

  Natural.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x = [];
      this._y = [];
    },
    lineEnd: function() {
      var x = this._x,
          y = this._y,
          n = x.length;

      if (n) {
        this._line ? this._context.lineTo(x[0], y[0]) : this._context.moveTo(x[0], y[0]);
        if (n === 2) {
          this._context.lineTo(x[1], y[1]);
        } else {
          var px = controlPoints(x),
              py = controlPoints(y);
          for (var i0 = 0, i1 = 1; i1 < n; ++i0, ++i1) {
            this._context.bezierCurveTo(px[0][i0], py[0][i0], px[1][i0], py[1][i0], x[i1], y[i1]);
          }
        }
      }

      if (this._line || (this._line !== 0 && n === 1)) this._context.closePath();
      this._line = 1 - this._line;
      this._x = this._y = null;
    },
    point: function(x, y) {
      this._x.push(+x);
      this._y.push(+y);
    }
  };

  // See https://www.particleincell.com/2012/bezier-splines/ for derivation.
  function controlPoints(x) {
    var i,
        n = x.length - 1,
        m,
        a = new Array(n),
        b = new Array(n),
        r = new Array(n);
    a[0] = 0, b[0] = 2, r[0] = x[0] + 2 * x[1];
    for (i = 1; i < n - 1; ++i) a[i] = 1, b[i] = 4, r[i] = 4 * x[i] + 2 * x[i + 1];
    a[n - 1] = 2, b[n - 1] = 7, r[n - 1] = 8 * x[n - 1] + x[n];
    for (i = 1; i < n; ++i) m = a[i] / b[i - 1], b[i] -= m, r[i] -= m * r[i - 1];
    a[n - 1] = r[n - 1] / b[n - 1];
    for (i = n - 2; i >= 0; --i) a[i] = (r[i] - a[i + 1]) / b[i];
    b[n - 1] = (x[n] + a[n - 1]) / 2;
    for (i = 0; i < n - 1; ++i) b[i] = 2 * x[i + 1] - a[i + 1];
    return [a, b];
  }

  function natural(context) {
    return new Natural(context);
  }

  function Step(context, t) {
    this._context = context;
    this._t = t;
  }

  Step.prototype = {
    areaStart: function() {
      this._line = 0;
    },
    areaEnd: function() {
      this._line = NaN;
    },
    lineStart: function() {
      this._x = this._y = NaN;
      this._point = 0;
    },
    lineEnd: function() {
      if (0 < this._t && this._t < 1 && this._point === 2) this._context.lineTo(this._x, this._y);
      if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
      if (this._line >= 0) this._t = 1 - this._t, this._line = 1 - this._line;
    },
    point: function(x, y) {
      x = +x, y = +y;
      switch (this._point) {
        case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
        case 1: this._point = 2; // proceed
        default: {
          if (this._t <= 0) {
            this._context.lineTo(this._x, y);
            this._context.lineTo(x, y);
          } else {
            var x1 = this._x * (1 - this._t) + x * this._t;
            this._context.lineTo(x1, this._y);
            this._context.lineTo(x1, y);
          }
          break;
        }
      }
      this._x = x, this._y = y;
    }
  };

  function step(context) {
    return new Step(context, 0.5);
  }

  function stepBefore(context) {
    return new Step(context, 0);
  }

  function stepAfter(context) {
    return new Step(context, 1);
  }

  var slice$2 = Array.prototype.slice;

  function none(series, order) {
    if (!((n = series.length) > 1)) return;
    for (var i = 1, s0, s1 = series[order[0]], n, m = s1.length; i < n; ++i) {
      s0 = s1, s1 = series[order[i]];
      for (var j = 0; j < m; ++j) {
        s1[j][1] += s1[j][0] = isNaN(s0[j][1]) ? s0[j][0] : s0[j][1];
      }
    }
  }

  function none$1(series) {
    var n = series.length, o = new Array(n);
    while (--n >= 0) o[n] = n;
    return o;
  }

  function stackValue(d, key) {
    return d[key];
  }

  function stack() {
    var keys = constant$1([]),
        order = none$1,
        offset = none,
        value = stackValue;

    function stack(data) {
      var kz = keys.apply(this, arguments),
          i,
          m = data.length,
          n = kz.length,
          sz = new Array(n),
          oz;

      for (i = 0; i < n; ++i) {
        for (var ki = kz[i], si = sz[i] = new Array(m), j = 0, sij; j < m; ++j) {
          si[j] = sij = [0, +value(data[j], ki, j, data)];
          sij.data = data[j];
        }
        si.key = ki;
      }

      for (i = 0, oz = order(sz); i < n; ++i) {
        sz[oz[i]].index = i;
      }

      offset(sz, oz);
      return sz;
    }

    stack.keys = function(_) {
      return arguments.length ? (keys = typeof _ === "function" ? _ : constant$1(slice$2.call(_)), stack) : keys;
    };

    stack.value = function(_) {
      return arguments.length ? (value = typeof _ === "function" ? _ : constant$1(+_), stack) : value;
    };

    stack.order = function(_) {
      return arguments.length ? (order = _ == null ? none$1 : typeof _ === "function" ? _ : constant$1(slice$2.call(_)), stack) : order;
    };

    stack.offset = function(_) {
      return arguments.length ? (offset = _ == null ? none : _, stack) : offset;
    };

    return stack;
  }

  function expand(series, order) {
    if (!((n = series.length) > 0)) return;
    for (var i, n, j = 0, m = series[0].length, y; j < m; ++j) {
      for (y = i = 0; i < n; ++i) y += series[i][j][1] || 0;
      if (y) for (i = 0; i < n; ++i) series[i][j][1] /= y;
    }
    none(series, order);
  }

  function silhouette(series, order) {
    if (!((n = series.length) > 0)) return;
    for (var j = 0, s0 = series[order[0]], n, m = s0.length; j < m; ++j) {
      for (var i = 0, y = 0; i < n; ++i) y += series[i][j][1] || 0;
      s0[j][1] += s0[j][0] = -y / 2;
    }
    none(series, order);
  }

  function wiggle(series, order) {
    if (!((n = series.length) > 0) || !((m = (s0 = series[order[0]]).length) > 0)) return;
    for (var y = 0, j = 1, s0, m, n; j < m; ++j) {
      for (var i = 0, s1 = 0, s2 = 0; i < n; ++i) {
        var si = series[order[i]],
            sij0 = si[j][1] || 0,
            sij1 = si[j - 1][1] || 0,
            s3 = (sij0 - sij1) / 2;
        for (var k = 0; k < i; ++k) {
          var sk = series[order[k]],
              skj0 = sk[j][1] || 0,
              skj1 = sk[j - 1][1] || 0;
          s3 += skj0 - skj1;
        }
        s1 += sij0, s2 += s3 * sij0;
      }
      s0[j - 1][1] += s0[j - 1][0] = y;
      if (s1) y -= s2 / s1;
    }
    s0[j - 1][1] += s0[j - 1][0] = y;
    none(series, order);
  }

  function ascending$1(series) {
    var sums = series.map(sum$1);
    return none$1(series).sort(function(a, b) { return sums[a] - sums[b]; });
  }

  function sum$1(series) {
    var s = 0, i = -1, n = series.length, v;
    while (++i < n) if (v = +series[i][1]) s += v;
    return s;
  }

  function descending$2(series) {
    return ascending$1(series).reverse();
  }

  function insideOut(series) {
    var n = series.length,
        i,
        j,
        sums = series.map(sum$1),
        order = none$1(series).sort(function(a, b) { return sums[b] - sums[a]; }),
        top = 0,
        bottom = 0,
        tops = [],
        bottoms = [];

    for (i = 0; i < n; ++i) {
      j = order[i];
      if (top < bottom) {
        top += sums[j];
        tops.push(j);
      } else {
        bottom += sums[j];
        bottoms.push(j);
      }
    }

    return bottoms.reverse().concat(tops);
  }

  function reverse(series) {
    return none$1(series).reverse();
  }

  function define(constructor, factory, prototype) {
    constructor.prototype = factory.prototype = prototype;
    prototype.constructor = constructor;
  }

  function extend(parent, definition) {
    var prototype = Object.create(parent.prototype);
    for (var key in definition) prototype[key] = definition[key];
    return prototype;
  }

  function Color() {}

  var darker = 0.7;
  var brighter = 1 / darker;

  var reHex3 = /^#([0-9a-f]{3})$/;
  var reHex6 = /^#([0-9a-f]{6})$/;
  var reRgbInteger = /^rgb\(\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*\)$/;
  var reRgbPercent = /^rgb\(\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*\)$/;
  var reRgbaInteger = /^rgba\(\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
  var reRgbaPercent = /^rgba\(\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
  var reHslPercent = /^hsl\(\s*([-+]?\d+(?:\.\d+)?)\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*\)$/;
  var reHslaPercent = /^hsla\(\s*([-+]?\d+(?:\.\d+)?)\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
  var named = {
    aliceblue: 0xf0f8ff,
    antiquewhite: 0xfaebd7,
    aqua: 0x00ffff,
    aquamarine: 0x7fffd4,
    azure: 0xf0ffff,
    beige: 0xf5f5dc,
    bisque: 0xffe4c4,
    black: 0x000000,
    blanchedalmond: 0xffebcd,
    blue: 0x0000ff,
    blueviolet: 0x8a2be2,
    brown: 0xa52a2a,
    burlywood: 0xdeb887,
    cadetblue: 0x5f9ea0,
    chartreuse: 0x7fff00,
    chocolate: 0xd2691e,
    coral: 0xff7f50,
    cornflowerblue: 0x6495ed,
    cornsilk: 0xfff8dc,
    crimson: 0xdc143c,
    cyan: 0x00ffff,
    darkblue: 0x00008b,
    darkcyan: 0x008b8b,
    darkgoldenrod: 0xb8860b,
    darkgray: 0xa9a9a9,
    darkgreen: 0x006400,
    darkgrey: 0xa9a9a9,
    darkkhaki: 0xbdb76b,
    darkmagenta: 0x8b008b,
    darkolivegreen: 0x556b2f,
    darkorange: 0xff8c00,
    darkorchid: 0x9932cc,
    darkred: 0x8b0000,
    darksalmon: 0xe9967a,
    darkseagreen: 0x8fbc8f,
    darkslateblue: 0x483d8b,
    darkslategray: 0x2f4f4f,
    darkslategrey: 0x2f4f4f,
    darkturquoise: 0x00ced1,
    darkviolet: 0x9400d3,
    deeppink: 0xff1493,
    deepskyblue: 0x00bfff,
    dimgray: 0x696969,
    dimgrey: 0x696969,
    dodgerblue: 0x1e90ff,
    firebrick: 0xb22222,
    floralwhite: 0xfffaf0,
    forestgreen: 0x228b22,
    fuchsia: 0xff00ff,
    gainsboro: 0xdcdcdc,
    ghostwhite: 0xf8f8ff,
    gold: 0xffd700,
    goldenrod: 0xdaa520,
    gray: 0x808080,
    green: 0x008000,
    greenyellow: 0xadff2f,
    grey: 0x808080,
    honeydew: 0xf0fff0,
    hotpink: 0xff69b4,
    indianred: 0xcd5c5c,
    indigo: 0x4b0082,
    ivory: 0xfffff0,
    khaki: 0xf0e68c,
    lavender: 0xe6e6fa,
    lavenderblush: 0xfff0f5,
    lawngreen: 0x7cfc00,
    lemonchiffon: 0xfffacd,
    lightblue: 0xadd8e6,
    lightcoral: 0xf08080,
    lightcyan: 0xe0ffff,
    lightgoldenrodyellow: 0xfafad2,
    lightgray: 0xd3d3d3,
    lightgreen: 0x90ee90,
    lightgrey: 0xd3d3d3,
    lightpink: 0xffb6c1,
    lightsalmon: 0xffa07a,
    lightseagreen: 0x20b2aa,
    lightskyblue: 0x87cefa,
    lightslategray: 0x778899,
    lightslategrey: 0x778899,
    lightsteelblue: 0xb0c4de,
    lightyellow: 0xffffe0,
    lime: 0x00ff00,
    limegreen: 0x32cd32,
    linen: 0xfaf0e6,
    magenta: 0xff00ff,
    maroon: 0x800000,
    mediumaquamarine: 0x66cdaa,
    mediumblue: 0x0000cd,
    mediumorchid: 0xba55d3,
    mediumpurple: 0x9370db,
    mediumseagreen: 0x3cb371,
    mediumslateblue: 0x7b68ee,
    mediumspringgreen: 0x00fa9a,
    mediumturquoise: 0x48d1cc,
    mediumvioletred: 0xc71585,
    midnightblue: 0x191970,
    mintcream: 0xf5fffa,
    mistyrose: 0xffe4e1,
    moccasin: 0xffe4b5,
    navajowhite: 0xffdead,
    navy: 0x000080,
    oldlace: 0xfdf5e6,
    olive: 0x808000,
    olivedrab: 0x6b8e23,
    orange: 0xffa500,
    orangered: 0xff4500,
    orchid: 0xda70d6,
    palegoldenrod: 0xeee8aa,
    palegreen: 0x98fb98,
    paleturquoise: 0xafeeee,
    palevioletred: 0xdb7093,
    papayawhip: 0xffefd5,
    peachpuff: 0xffdab9,
    peru: 0xcd853f,
    pink: 0xffc0cb,
    plum: 0xdda0dd,
    powderblue: 0xb0e0e6,
    purple: 0x800080,
    rebeccapurple: 0x663399,
    red: 0xff000