Abstract: Toy apparatus for the formation of 2- and 3-dimensional geometrical structures and including a plurality of substantially spherical connector members each having a plurality of radial sockets or prongs arranged around a central point in the connector member, a plurality of slender connecting members in groups of different lengths and having opposite ends to fit in the sockets or to receive the prongs, said sockets or prongs of each connector member body being arranged in patterns that enable the connector members to be interconnected by the connecting member to form tetrahedron, octahedron and cube structures.