              deltaTime = newTime - (time || newTime);
      time = newTime;
// clear canvas
      context.clearRect(0, 0, canvas.width, canvas.height);
// create new particles
      var amount = particleRate * deltaTime;
      for (var i = 0; i < amount; i++) {
        var pos = pointOnHeart(Math.PI - 2 * Math.PI * Math.random());
        var dir = pos.clone().length(settings.particles.velocity);
        particles.add(canvas.width / 2 + pos.x, canvas.height / 2 - pos.y, dir.x, -dir.y);
      }
/