Are you ready to flip out? Hexaflexagons are six-sided, flat paper models that can be made to reveal hidden images through a series of flexes and folds. Flexago

Japanese origami expert Hisao Fukui shows you how to create incredibly realistic paper birds and flying insects, a winged dinosaur and even an undulating Chines

The first of fifteen updated editions of the collected Mathematical Games of Martin Gardner, king of 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