This is my spiral for zen photon garden

config.js

// Constants for you to play around with :)
scope.ctx = {
  x0:           ['cx', 0, -100, 100],
  y0:           ['cy', 0, -100, 100],
  radius0:      [100, 10, 200], // pixels
  finalRadius:  [200, 10, 400],
  theta0:       [0, 0, Math.PI*2],   // in radians. 2*PI = full circle
  segments:     [10, 3, 50],
  segLength:    [1, 0,  10, 0.1],  // 1 makes a continuous spiral
  numCircles:   [1, 0.1, 3, 0.1],
  transmissive: [0.5, 0, 1],
  diffuse:      [0,   0, 1],
  reflective:   [0.5, 0, 1]
};

zenflower.js

// calculated, cached constants
var deltaTheta  = (Math.PI * 2) * c.numCircles / c.segments
  , deltaRadius = (c.finalRadius - c.radius0) / c.segments;

// Create the walls
for (var i=0; i < segments; i+=1) {
  var theta1  = c.theta0  + i * deltaTheta
    , theta2  = theta1    +     deltaTheta * c.segLength
    , radius1 = c.radius0 + i * deltaRadius
    , radius2 = radius1   +     deltaRadius + 20;

  add_wall(Math.cos(theta1) * radius1 + c.x0, 
           Math.sin(theta1) * radius1 + c.y0, 
           Math.cos(theta2) * radius2 + c.x0, 
           Math.sin(theta2) * radius2 + c.y0, 
           c.transmissive, c.reflective, c.diffuse);
  add_wall(-Math.cos(theta1) * radius1 + c.x0, 
           Math.sin(theta1) * radius1 + c.y0, 
           -Math.cos(theta2) * radius2 + c.x0, 
           Math.sin(theta2) * radius2 + c.y0, 
           c.transmissive, c.reflective, c.diffuse);
}