public class Game extends Panel {
   Box puck = new Box(puckColor);
   Game() {
    MouseMotionListener movePuck = 
      new MouseMotionAdapter() {
	public void mouseMoved(MouseEvent e) {
	  int x = e.getX();
	  int y = getSize().height - 
	             puck.getSize().height;
	  puck.setLocation(x, y);
	}
    };
    addMouseMotionListener(movePuck);
  }
}