Codex Gamicus

Stones is a game developed by Michael C. Miller and released in 1991 as part of Microsoft's Windows Entertainment Pack. Some people think this game is a variant of the Chinese game, Ishido, but it was actually developed independently before Ishido was released. Its object is to place 90 tiles, or "stones", on a board. A tile can only be placed if it shares two of three attributes - color, shape, or the like - with every adjacent tile. Wild tiles may be placed anywhere regardless of attributes. The game is won when all tiles are placed or when there are no valid spaces to place the next tile.