Undiluted Hocus-Pocus: The Autobiography of Martin Gardner

Begin with a strip of paper 11 inches long and 2.5 inches wide. Orient the strip so that the long sides form the top and bottom. Draw a line along the length of the strip half an inch from the top. Place a mark on this line half an inch from the left side, label A. From A, draw five more marks, each 1.75 inches from the last; label them B-F. Draw one last mark 7/8 of an inch after F, called G. Draw a perpendicular line from G across the strip widthwise. Draw a diagonal line that is 1.75 inches long from mark F to the line extending from G; call the point of intersection H.