The new and enlarged edition of this popular book gives detailed instructions for making a wide variety of models illustrating elementary mathematics. Nothing of value in the first edition has been omitted: dissections, paper-folding, curve-stitching, the drawing of loci and envelopes, the construction of plane tesselations, polyhedra, and ruled surfaces are all included. Complete plans and nets are given for all regular, Archimedean, and stellated polyhedra, together with compound solids of various kinds. The section of machines has been considerably enlarged, and now includes details of simple electric adding devices and analogue computers. There is also a completely new chapter on logical devices. Linkages and pendulum machines for drawing lines and curves are described, and the book is fully illustrated with diagrams and plates of models in paper and cardboard, wood and 'perspex' plastic. All the models have first been successfully made in school classes or for demonstration before being used as illustrations in this intriguing and very useful book. -- from dust jacket.