​

function setup() {

  createCanvas(400, 400);

  ball = new Ball(random(width),random(height));

}

​

function draw() {

  background(220);

  ball.update();

  ball.show();

}

​

class Ball{

  constructor(x,y){

    this.pos = createVector(x,y);

    this.vel = createVector(0,0);

    this.acc = createVector(cos(random(0,2*PI)),sin(random(0,2*PI)));

  }

  update(){

    if (this.pos.x > width || this.pos.x < 0) this.vel.x *= -1;

    if (this.pos.y > height || this.pos.y < 0) this.vel.y *= -1;

    this.pos.add(this.vel);

    this.vel.add(this.acc);

    this.acc.mult(0.00001)

  }

  show(){

    stroke(0);

    fill(255,0,0);

    circle(this.pos.x,this.pos.y,10);

  }

}

​