Flexagons

The January 2012 issue of ‘The College Mathematics Journal’ is a Martin Gardner Special Issue. It includes three papers on flexagons which were introduced to a wide audience 50 years ago by Martin Gardner. For my paper see Gardner 13-cmj011-014-pook

Serious Fun with Flexagons

A substantially cheaper paperback edition of ‘Serious fun with flexagons. A compendium and guide.’ is now available from Springer to people who have access, through their libraries, to Springer ebooks. The text is identical to the original hardback edition. The book can be read online. Go to www.springer.com and search for Pook.

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Hooke’s Joint Flexagons

I’ve added a sub page on Hooke’s joint flexagons. Hooke’s joint flexagons were first described by Engel, who calls them ‘hybrid flexagons’, but ‘Hooke’s joint flexagons’ is more apposite. The characteristic feature of a Hooke’s joint flexagon is that adjacent leaves are hinged to either face of an ‘intermediate leaf’’ The hinges are at right angles so the intermediate leaf is a Hooke’s joint.

Serious Fun with Flexagons

My book ‘Serious Fun with Flexagons. A Compendium and Guide.” has now been published by Springer. For details see the Publications page. The book includes accurately drawn nets for over 100 flexagons, many of which have not previously been published. Photographs of flexagons in the book are reproduced in black and white. For colour versions of the photograps see the Serious Fun with Flexagons sub page.

Serious fun with flexagons. A companion and guide

My book ‘Serious fun with flexagons. A companion and guide.’ is duer to be published by Springer in July 2009.

A flexagon is a motion structure that has the appearance of a ring of hinged polygons. It can be flexed to display different pairs of faces, usually in cyclic order. Flexagons can be appreciated as toys or puzzles, as a recreational mathematics topic, and as the subject of serious mathematical study. Workable paper models of flexagons are easy to make and entertaining to manipulate. The mathematics of flexagons is complex, and how a flexagon works is not immediately obvious on examination of a paper model. Recent geometric analysis, included in the book, has improved theoretical understanding of flexagons, especially relationships between different types.

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 700 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.