let HIG = 400;

let balls = [];

let n = 60;

let i;

​

function setup() {

  createCanvas(WID,HIG);

  for (i=0; i<n;i++){

    balls[i] = new ball(i * 3);

  }

  print(width);

}

​

function draw() {

  background(220);

  for (i=0; i<balls.length;i++){

    balls[i].show();

    balls[i].move();  

  }

}

​

class ball {

  constructor(shade){

    this.x = WID/2;

    this.y = WID/2;

    this.d = 23;

    this.s = shade;

  }

    move() {

    this.x = this.x + random(-2,2);

    this.y = this.y + random(-2,2);

    if (this.x > WID - 2 * this.d) {this.x = WID - 2 * this.d;}

    if (this.x < 2 * this.d) {this.x = 2 * this.d;}

    if (this.y > HIG -2 * this.d) {this.y = HIG - 2 * this.d;}

    if (this.y < 2 * this.d) {this.x = 2 * this.d;}

  }

    show() {

      stroke(0);

      strokeWeight(2);

      fill(this.s);

      ellipse(this.x, this.y, this.d);

    }

}

​