= (function() {
    function Particle() {
      this.position = new Point();
      this.velocity = new Point();
      this.acceleration = new Point();
      this.age = 0;
    }
    Particle.prototype.initialize = function(x, y, dx, dy) {
      this.position.x = x;
      this.position.y = y;
      this.velocity.x = dx;
      this.velocity.y = dy;
      this.acceleration.x = dx * settings.particles.effect;
      this.acceleration.y = dy * settings.particles.effect;
      this.age = 0;
    };
 