Dear Dr. Mills,

The 17 wallpaper groups demonstrated using periodic tilings drawn by RepTiles. The tilings are all four-colorable, i.e. each has four equivalence classes of tiles, s.t. no two tiles of the same class share an edge. Moreover, the tilings have maximal symmetry, meaning that they is no topologically equivalent tiling with higher symmetry.

If you find these tilings too complex, then I could easily produce ones with less classes of tiles, but they look rather boring. Alternately, you can easily produce such pictures yourself using the RepTiles program. To convert RepTiles pictures in to postscript, simply choose the laserprinter with the macintosh chooser and then print the tilings to postscipt files by pressing the appropriate button in the printer dialog.

Best wishes
Daniel Huson

Below are listed examples of the seventeen plane symmetry groups, generated by Daniel Huson using his RepTile program.

**p1 **
**pm **
**pmm**
**pg **
**pgg**
**pmg**
**p2 **
**p3 **
**p31m**
**p3m1**
**p4 **
**p4g**
**p4m**
**p6 **
**p6m**
**cm **
**cmm**

am 3/5/95