Simple "game boards" were scratched into the ground or painted on stones or wooden boards.
Game boards inlaid with wood or stone are more elaborately worked.    

Fig. left: (Badisches Landesmuseum Karlsruhe: Spätmittelalter am Oberrhein. Alltag, Handwerk und Handel 1350-1525)
Fig. right: game board for Wurfzabel (=Backgammon, Trictrac, Puff), Freiburger Augustiner-Eremiten-Kloster. (Günter P. Fehring, Stadtarchäologie in Deutschland, Sonderheft der Zeitschrift "Archäologie in Deutschland")