Flexagons are hinged polygons that have the intriguing property of displaying different pairs of faces when they are flexed. Workable paper models of flexagons are easy to make and entertaining to manipulate. Flexagons have a surprisingly complex mathematical structure and just how a flexagon works is not obvious on casual examination of a paper model. Flexagons may be appreciated at three different levels. Firstly as toys or puzzles, secondly as a recreational mathematics topic and finally as the subject of serious mathematical study. This book is written for anyone interested in puzzles or recreational maths. No previous knowledge of flexagons is assumed, and the only pre-requisite is some knowledge of elementary geometry. An attractive feature of the book is a collection of nets, with assembly instructions, for a wide range of paper models of flexagons. These are printed full size and laid out so they can be photocopied.

• Cut-out-and-make models of flexagons can be made and enjoyed by anyone • Explains the mathematics behind flexagons

### Contents

1. Making and flexing flexagons; 2. Early history of flexagons; 3. Geometry of flexagons; 4. Hexaflexagons; 5. Hexaflexagon variations; 6. Square flexagons; 7. Introduction to convex polygon flexagons; 8. Typical convex polygon flexagons; 9. Ring flexagons; 10. Distorted polygon flexagons; 11. Flexahedra.

### Reviews

' … an excellent resource for anyone with little previous knowledge to understand the basics, but with enough detail to satisfy the interest of all but the most ardent mathmos.' Eureka

'Pook's book summarizes a great deal of what is known about flexagons of all shapes and types, and contains much new material … an excellent purchase for someone who already knows something about flexagons and wants to know more.' Ethan Berkove, Lafayette College

'This interesting book contains a wide collection of nets for making paper models of flexagons.' Zentralblatt MATH

'This book would be an excellent purchase for someone who already knows something about flexagons and wants to know more.' Society for Industrial and Applied Mathematics

'The main advantage of the book is that it gives a mathematical analysis of flexagons by using only elementary mathematical concepts. Thus this book will be very useful for anybody who is not a professional mathematician but wants to get some insight into the mathematical structure of these exciting puzzles.' EMS Newsletter

'… a thorough comprehensible work … keeps the text readable and easy to follow. … This book would be appropriate for anyone at the undergraduate level or higher, and would likely be enjoyed by anyone with an interest in recreational mathematics.' Mathematical Association of America Online