this.pos = createVector(x, y);

  this.vel = createVector(0, 0);

  this.acc = createVector(0, 0);

  this.mass = mass;

  this.applyForce = function(f) {

    this.acc.add(p5.Vector.div(f, this.mass));

  }

    this.update = function() {

    this.vel.add(this.acc);

    this.pos.add(this.vel);

    this.acc = createVector(0, 0);

  }

  this.draw = function() {

    fill(220);

    ellipse(this.pos.x, this.pos.y, 48, 48);

  }

}

​

var maxParticles = 6;

var particle = []

​

function setup() { 

  createCanvas(640, 480);

  for (var i = 0; i < maxParticles; i++) {

    particle.push(

      new Particle(

        (i + 1) * (width / (maxParticles + 1)), 

        //i * (height / (maxParticles + 1))));

        height / 2,

            random(1, 3)));

  }

} 

​

function draw() { 

  background(160);

  var gravity = createVector(0, 0.1);

  for (var i = 0; i < maxParticles; i++) {

    particle[i].applyForce(gravity);

    particle[i].update();

    particle[i].draw();  

  }

}