In the 2260s, a three-dimensional version of the game was often played in the recreation room aboard the USS Enterprise. (TOS: "The Naked Time" , "Charlie X" , "The Conscience of the King" , "The Alternative Factor" , "The Trouble with Tribbles" , "By Any Other Name" ) 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." (VOY: "Alter Ego")