public void addBullets() {
		if (! ship.moving()) return;
		
		for (int i = 1; i < 4; ++i) {
			TimedObject bullet = new TimedObject(
					random.nextInt(50 / difficultyFactor));

			bullet.position.x = ship.position.x;
			bullet.position.y = ship.position.y;

			bullet.width = 5;
			bullet.height = 5;

			int speed = 2 * i;
			bullet.push(speed * ship.xOffset, speed * ship.yOffset);

			bullets.add(bullet);
		}
	}