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@mbostock
Forked from enjalot/index.html
Last active Feb 9, 2016
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Square Circle Spiral Illusion
license: gpl-3.0
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
background: #888;
}
rect {
fill: none;
stroke: #000;
stroke-width: 2.5px;
}
.square:nth-child(2n + 1) rect {
stroke: #fff;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var w = 960,
h = 500,
start = Date.now();
var rings = [
{radius: 65 * 1, width: 16, speed: -3e-2},
{radius: 65 * 2, width: 16, speed: -2e-2},
{radius: 65 * 3, width: 16, speed: -1e-2},
{radius: 65 * 4, width: 16, speed: 1e-2},
{radius: 65 * 5, width: 16, speed: 2e-2},
{radius: 65 * 6, width: 16, speed: 3e-2}
];
var svg = d3.select("body").append("svg")
.attr("width", w)
.attr("height", h)
.append("g")
.attr("transform", "translate(" + w / 2 + "," + h / 2 + ")scale(.6)");
var ring = svg.selectAll("g")
.data(rings)
.enter().append("g")
.attr("class", "ring")
.each(ringEnter);
d3.timer(function() {
var elapsed = Date.now() - start,
rotate = function(d) { return "rotate(" + d.speed * elapsed + ")"; };
ring
.attr("transform", rotate)
.selectAll("rect")
.attr("transform", rotate);
});
function ringEnter(d, i) {
var n = Math.floor(2 * Math.PI * d.radius / d.width * Math.SQRT1_2),
k = 360 / n;
d3.select(this).selectAll("g")
.data(d3.range(n).map(function() { return d; }))
.enter().append("g")
.attr("class", "square")
.attr("transform", function(_, i) { return "rotate(" + i * k + ")translate(" + d.radius + ")"; })
.append("rect")
.attr("x", -d.width / 2)
.attr("y", -d.width / 2)
.attr("width", d.width)
.attr("height", d.width);
}
</script>
@AmusingTeebs
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AmusingTeebs commented Sep 25, 2013

Trippy...

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