let xspeed = 10;

let color1 = 255;

let cspeed = 6.375;

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

  x += xspeed;

  color1 += cspeed;

  color1 = constrain(color1, 0, 255);

  if (x > width || x < 0) {

    cspeed *= -1;

    xspeed *= -1;

  }

​

  fill(color1);

​

  ellipse(x, height / 2, 20, 20);

}