Four-dimensional chess

Four-dimensional chess, or 4-D chess, was a Time Lord variant of the Earthly game of chess which was "very popular" on Gallifrey.

It shared the basic rules of Earth chess, but also involved "multiple levels", "the ability to dematerialise pieces from the board and have them materialise elsewhere on later turns of the game", and time-travelling pieces. (GAME: )

Rollo was a skilled 4-D chess player. (GAME: )