image upload no size limit http://postimage.org/] [/PLAIN] [Broken] image hosting adult The answer is saying the following, initial reflection + 0 or 1 further reflection only, not at lower surface must be straight and reach within 1cm of end. --------- How come 0 or 1 reflection only ? The length is long to take only one reflection! I also attached a photo of how I think it should be drawn. Thank you for your help!