KaleidoTileSave
Software for Macintosh and SGI to create and manipulate tessellations of the sphere, Euclidean plane and hyperbolic plane, and to see how the Platonic solids are related to tessellations. http://www.geom.uiuc.edu/software/dow...
Tiling Plain and FancySave
Tiling from the mathematical and historical viewpoint by Steve Edwards. Provides a number of examples of various types of tiles that tile the plane and includes periodic tiling plus Penrose's aperiodic tiles. http://www2.spsu.edu/math/tile/