var opacity = 1;

​

function setup() {

  createCanvas(400, 400);

  background(255);

  stroke(0, 15);

  noFill();

  t = 0;

}

​

function draw() {

  translate(width/2, height/2);

  beginShape();

  for (var i = 0; i < 300; i++) {

    var ang = map(i, 0, 200, 0, TWO_PI);

    var rad = 200 * noise(i * mouseX*0.0001, t * 0.005);

    var x = rad * cos(ang);

    var y = rad * sin(ang);

    curveVertex(x, y);

  }

  endShape(CLOSE);

​

  t += 1;

​

  // clear the background every 600 frames using mod (%) operator

  if (frameCount % 600 == 0) {

    t -=1;

    rect(0,0,width, height);

    tint(255, opacity ++);

  }

​

}

 function keyPressed(){

  clear();

 }