Abstract: A hand-manipulatable three-dimensional puzzle includes a body in the shape of an octahedron and constituted of a plurality of elements interconnected together to permit rotation of one-half of the body with respect to the other half along each of three orthogonal planes symmetrically passing through the body. In a preferred embodiment, the octahedron-shaped body is defined by a pair of interpenetrating tetrahedra presenting the outline appearance of a six-pointed star whenever the device is viewed along any one of the eight axes of the inter-penetrating tetrahedra.