With Holtz, you can play the abstract strategy games Zèrtz and
Dvonn. Both of them are board games invented by Kris Burm, and are
part of the GIPF project.

Recently a third game called Relax was added. It is based on the
board game "Take It Easy" and can be played alone as well as with
up to ten players.

Homepage:
https://holtz.sourceforge.io/
