Abstract: Building components that interconnect with one another to form a building are disclosed. The building components can be arranged in an almost limitless number of combinations to construct differently-shaped buildings. Embodiments include foundation blocks with vertically extending floor supports that form an open space beneath the floor when the floor tiles are placed on the floor supports. Alternate embodiments include side foundation blocks with recesses that form connecting passageways between the floor chase and open chases formed in the walls. Still other embodiments include side foundation blocks with abutment portions that inhibit the floor tiles from moving horizontally outside the foundation.