var y = 83;

var Xspeed = 3;

var Yspeed = 3;

let r, g, b;

​

function setup() {

  createCanvas(600, 400);

}

​

function draw() {

  background(0);

  stroke(255);

  strokeWeight(1);

  // noFill();

​

  // check x cord

  if (x > width - 20 || x < 20) {

    Xspeed = Xspeed * -1;

    r = random(64, 255);

  }

  // check y cord

  if (y > height - 20 || y < 20) {

    Yspeed = Yspeed * -1;

    r = random(64, 255);

  }

​

  g = map(y, 0, 400, 0, 128);

  b = map(x, 0, 600, 64, 200);

​

  fill(r, g, b);

​

  x = x + Xspeed;

  y = y + Yspeed;

​

  ellipse(x, y, 40, 40);

}

​