"Poly-cyclo-epicycloidal & Other Geometric Curves" By Edwin W. Alabone M.D.; D.Sc; F.R.M.S. &c. Second edition. 1912 This book is full of beautiful reproductions of spirograph patterns and other fascinating history of 19'th century spirography. One use was to make non-reproducable engravings which served as marks of authenticity on stock certificates. The non-reproducability being a side effect of the fact the no one could reverse engineer to figure out what settings were used to produce a particular pattern.