corner-wave.js

var canvElt, 
	numFrames = 120, 
	duration = 3000,
	recording = true,
	time = 0

function setup() {
	canvElt = createCanvas(600, 600).elt;

	noStroke();
}

function draw() {
	background(255);
	time = ((frameCount+frameCount/2)%numFrames)/numFrames

	blendMode(DIFFERENCE)
	var numCircs = 10;
  for(var j=0; j<4; j++) {
    translate(width/2,height/2)
    rotate(PI/2)
    translate(-width/2,-height/2)
    fill(rgb[k])
    for (var i = 0; i < numCircs+4; i++) {
      var r = ((numCircs-i+time*4))/numCircs * width * 1.4142;
      fill(i%2 * 255)
      r > 0 ? ellipse(0,0,2*r,2*r) : null;
    }		
  }	
	blendMode(BLEND)
}