This is an Unix adaptation of the SC hexxagon, at least for the look and the characteristics. With, more, a cool and nice humour. The author, the french Michaël d'Auria says that X-agone is a mind game on Unix, made in C on X11, in 1995, with his friends Gontran Baerts and Jeff Devret (the group BDCreator).
It may be played human against computer, human against human on the same computer, human against human on two computers.