Concentric circles for zen photon garden

code.js

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

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

config.js

// Constants for you to play around with :)
var 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, 1, 5, 1],
  transmissive: [0.5, 0, 1],
  diffuse:      [0,   0, 1],
  reflective:   [0.5, 0, 1],
  slant:        [0, -10, 10]
};