"Most of them were under a white awning, where a game of four-dimensional chess was in progress. This highly intellectual game, in which the board and pieces had four spatial dimensions and existed only in the imaginations of the players, had been introduced to the school several years before by Zhilin, the same Zhilin who was now engineer on the trans-Martian voyager Takhmasik The senior classmen were quite fond of the game, but by no means could everyone play it. On the other hand, anyone who felt like it could kibitz. The shouts of the kibitzers filled the entire park."
Noon: 22nd Century