Strat-O-Sphere (1990)

David Royffe's first game, which later evolved into his Pylos. With four players, each player has 23 spheres (marbles). The spheres are used to build a pyramid layer by layer on a central grid. In rotation, each player adds a sphere to form a chain of their color. When a layer is complete the next player starts a new chain on the next layer up. Each sphere is now supported by four spheres below, one or more of which must be of the same color. If a player is blocked they must fill all the empty places in that layer. However there is an option to sacrifice a sphere into the tomb. The player who places the final sphere at the top of the pyramid wins. There is a puzzle version for one. With two players, each player plays with 46 spheres in two colors.