Players add marbles two at a time into any of five chutes in a wooden tower. Once all of each players twenty marbles are distributed, blindly (the tower is a solid block of wood), the tower is slowly slid along a grooved path that distributes the marbles in the order they were placed into an even grid of depressions. Each player scores for marbles that appear in a row of four, either diagonally or orthogonally, and any line of five counts as two four-in-a-rows. It's a quick game of memory and patterns, and it engages blocking and building strategies.