Nickel is a perfect-information strategy game for two players designed to be played with Looney Pyramids. A 5×5 grid is randomly filled at the beginning of the game with 25 pyramids, each of which consists of a unique combination of color and orientation (N, E, W, S, standing-up). Players then alternate turns removing one of the pyramids on the board and replacing it with one of their tokens. Moves are restricted based on the pyramid that your opponent has just removed: you must play in a square that matches this just-removed pyramid in either orientation or color. The goal is to form an L shape or a straight line of your tokens. An alternate win condition is to leave your opponent without a legal play at the beginning of his turn.
—description from the designer