Lots of articles on games, chess, puzzles, popular mathematics, geometrical problems and brain teasers, mostly in the Journal of Recreational Mathematics.
Several "serious" mathematical articles
Several books on geometrical problems (popular mathematics), privately published
Poetry book "Wecker im Kopf", privately published E-BOOK: poetry book "Wecker im Kopf", published by Smashwords, ISBN 978-1-62209-590-2 and Amazon.
Board games (hands-on as well as computer games; not all are displayed on my web pages)
Puzzles (made from metal, plastic, wood)
I have built a real (1.5 m high) Turing Machine from a metal construction set, some wood and some plastic tubes. It is exhibited at the entrance of the software department of the University of Heidelberg, Germany.
Publications and web sites which quote and discuss some of my stuff
Book "Polyominoes" by Solomon Golomb
Book "Index to Mathematical Problems" 1980-1984 by Stanley Rabinowitz
Zillions of Games (board games software development environment, hundreds of games)
Math Puzzles by Ed Pegg, especially mazes and tilings