US Patent 7559821 Building block

The present invention provides such a spherical block structure wherein each spherical block is made up of three intersecting rings corresponding to the three axes (x, y and z) of the sphere. Each ring comprises eight subunits with two of those subunits being shared with each of the other two rings. The spherical block structure created by the intersecting rings results in a hollow center with eight cavities radiating outward, the cavities providing a location for the disposition of a connection means whereby individual spherical blocks may be releasably connected to form larger structures.