let b = 0;

let c = 255;

let border_color;

​

let a_speed = 1;

let b_speed = 2;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

​

  stroke(0);

  border_color = fill(c);

  ellipse(a, b, 32, 32);

​

  a += a_speed;

  b += b_speed;

​

  if (a > width || a < 0) {

    a_speed *= -1;

  }

​

  if (b > height || b < 0) {

    b_speed *= -1;

  }

}

​