In the Olden Tymes, Count Regula is drawn and quartered for killing twelve virgins in his dungeon torture chamber. Thirty-five years later, he comes back to seek revenge on the daughter of his intended thirteenth victim and the son of his prosecutor in order to attain immortal life.
This profusely illustrated book is arranged in a logical order appropriate for a textbook on the geometry of flexagons. It is written so that it can be enjoyed at both the recreational mathematics level, and at the serious mathematics level. The only prerequisite is some knowledge of elementary geometry, including properties of polygons. A feature of the book is a compendium of over 100 nets for making paper models of some of the more interesting flexagons, chosen to complement the text. These are accurately drawn and reproduced at half full size. Many of the nets have not previously been published. Instructions for assembling and manipulating the flexagons are included.