createCanvas(150, 150);

  background(240);

}

let x = 10;

let y = 75;

let xDir = 3;

let yDir = 3;

function draw() {

  background(240);

  ellipse(x, y, 20);

  x = x + xDir;

  y = y + yDir;

  if ((x > width-10) || (x < 10)) {

    //print("we are on the canvas")

    //print("we are off the canvas")

    xDir = xDir*(-1);

  }

  if ((y > height-10) || (y < 10) ){

    yDir = yDir*(-1)

  }

}

​