function Circle(x, y) {
  this.x = x;
  this.y = y;
  this.r = floor(random(0, 255));
  this.g = floor(random(0, 255));
  this.b = floor(random(0, 255));
  this.radius = 15;
  this.minSpeed = 1;
  this.maxSpeed = 5;
  this.speedX = random(-this.maxSpeed, this.maxSpeed);
  this.speedY = random(-this.maxSpeed, this.maxSpeed);
  this.timer = 0;

  this.getColor = function () {
    this.r = floor(random(0, 255));
    this.g = floor(random(0, 255));
    this.b = floor(random(0, 255));
  }

  this.update = function () {
    this.timer++
    fill(this.r, this.g, this.b);
    ellipse(this.x, this.y, this.radius * 2, this.radius * 2);

    this.x = this.x + this.speedX;
    this.y = this.y + this.speedY;

    if (this.timer == 200) {
      this.radius = 30;
    }
    if (this.timer == 250) {
      this.radius = 0;
      circles.push(new Circle(width/2, height/2));
    }
    if (this.timer == 400) {
      this.radius = 10;
      this.timer = 0;
    }

    if (this.x + this.radius > width) {
      this.speedX = random(-this.minSpeed, -this.maxSpeed);
      this.getColor();
    } else if (this.x - this.radius < 0) {
      this.speedX = random(this.minSpeed, this.maxSpeed);
      this.getColor();
    } else if (this.y + this.radius > height) {
      this.speedY = random(-this.minSpeed, -this.maxSpeed);
      this.getColor();
    } else if (this.y - this.radius < 0) {
      this.speedY = random(this.minSpeed, this.maxSpeed);
      this.getColor();
    }
  }
}