function setup() {

  createCanvas(windowWidth,

               windowHeight);

  background(234, 234, 234);

}



function draw() {

  noStroke();



  //adding value to red and green.

  fill(frameCount, 128 + frameCount, 128, 10);



  //adding value to the radius of the circle.

  ellipse(150, 80, frameCount);

}