public void move(long delta) {
		// if we're moving left and have reached the left hand side
		// of the screen, don't move
		if ((dx < 0) && (x < 10)) {
			return;
		}
		// if we're moving right and have reached the right hand side
		// of the screen, don't move
		if ((dx > 0) && (x > 750)) {
			return;
		}
		
		super.move(delta);
	}