Flexagons inside out / Les Pook.

Title from publisher's bibliographic system (viewed on 05 Oct 2015).

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 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.