Tic-tac-toe

Tic-tac-toe is a Human game in which two players try to fill three boxes in a row within a 3&times;3 square grid with either an X or an O (vertically, diagonally, or horizontally).

In the 2260s, a three-dimensional version of the game was often played in the recreation room aboard the USS Enterprise (NCC-1701). 

In 2373, when Harry Kim referred to kal-toh as "Vulcan chess", Tuvok commented that "Kal-toh is to chess as chess is to tic tac toe."