Flexagons Inside Out

Flexagons, paper models that can be bent in different ways to change their shape, are easy to make and work in surprising ways. This book contains numerous diagrams that the reader can photocopy and use to construct a variety of fascinating flexagons. The author also explains the mathematics behind these amazing creations. Although knowledge of the technical details requires a mathematical background, the models can be made and used by anyone. Flexagons appeals to all readers interested in puzzles and recreational mathematics.

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.

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.

Flexagons are paper models that can be flexed in different ways to change their shape. They are easy to make, and work in surprising ways. This book explains the maths behind flexagons and includes instructions to make them. Flexagons will appeal to anyone interested in puzzles or recreational maths.