下麵是我在本文的英文版貼出的地方加的提示，同樣適用於這裏：

A courtesy reminder I have been often surprised by how poorly professionals read very short essays....so as a courtesy reminder for anyone who would come to comment: Please answer the question whether the laser beam would hit the hole and the beam A or B at the same time as a proof that you do have the ability to understand this short essay.....