Black Hole, initially designed as a paper-and-pencil game, is played on a triangular board of 21 cells. Two players alternate turns placing a numbered disc of their color onto an empty space. Discs are numbered 1-10 and must be placed in numerical order. When all the discs have been placed, the game ends. The one board space that remains empty is the "Black Hole"; each player sums the values of his discs surrounding the Black Hole, and the player with the lower sum wins. Black Hole includes two rule variants: In the first, players can place their discs in any order, and in the second players place their discs face down and shuffle them, drawing a disc at random each turn, then placing it.