let y;

​

let xspeed = 1;

let yspeed = 2;

​

function setup() {

  createCanvas(400, 400);

  //position

  x = width / 2;

  y = height / 2;

}

​

function draw() {

  background(0);

​

  drawball();

  speed();

  bounce();

}

​

function drawball() {

  noStroke();

  ellipse(x, y, 50, 50);

}

​

function speed() {

  x += xspeed;

  y += yspeed;

}

​

function bounce() {

  if (x <= 0 || x >= width) {

    xspeed *= -1;

    fill(random(255), random(255), random(255));

  }

  if (y <= 0 || y >= height) {

    yspeed *= -1;

    fill(random(255), random(255), random(255));

  }

}

​