var numRows;

var numCirclesPerRow;

var rad;

var speed;

​

function setup() {

  createCanvas(800, 800);

  colorMode(HSB);

  background(0);

  numRows = 30;

  numCirclesPerRow = 30;

  rad = 20;

  speed = 0.05;

}

​

function draw() {

  background(0);

  for (var r=0; r<numRows; r++) {

    for (var i=0; i<numCirclesPerRow; i++) {

      var cx = map(i, 0, numCirclesPerRow, -100, width+100);

      var cy = map(r, 0, numRows, -100, height+100);

      var distFromCenter = dist(cx, cy, width/2, height/2);

      var angle = frameCount*speed + distFromCenter*0.02 + i*0.1;

      var x = cx + rad * cos(angle);

      var y = cy + rad * sin(angle);

      var offset = map(frameCount, 0, TWO_PI/speed, 0, 255);

      var h_ = (distFromCenter + offset) % 255;

      var s_ = 200;

      var b_ = 200;

      fill(h_, s_, b_);

      ellipse(x, y, 12, 12);

    }  

  }

}