let dx = 5;

​

let y = 100;

let dy = 2;

​

let h = 0;

let dh = 1;

let r = 1;

let dr = 0.4;

​

​

function setup() {

  createCanvas(300, 300);

  // frameRate(4);

  rectMode(CENTER);

  background(255);

  colorMode(HSB);

}

​

function draw() {

  x += dx;

  y += dy;

  r += dr;

  h += dh;

  fill(h, 100, 100);

  noStroke();

  circle(x, y, r);

  if ((x > width) || (x < 0)) {

    dx = -dx;

  }

  if ((y > height) || (y < 0)) {

    dy = -dy;

  }

  if ((h > 360) || (h < 0)) {

    dh = -dh;

  }

  if ((r > 30) || (r < 1)) {

    dr = -dr;

  }

​

}