let y = 100

xSpeed = 1

ySpeed = 3.3

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(255)

  x = x + xSpeed

  y = y + ySpeed

  if ((x > width) || (x < 0)) {

    xSpeed = xSpeed * -1

  }

  if ((y > height) || (y < 0)) {

    ySpeed = ySpeed * -1

  }

  stroke(0)

  fill(175)

  ellipse(x, y, 16, 16)

}