There is an interior void with a cubical shape inside this icosahedron. The cube is maximally enclosed within it (minus a wall thickness of 50 mil) so that each of its vertices lie at the center of one of the icosahedron's faces. The shape models the directional bases of Rudolf Laban's theory of choreography called [Space Harmony]( http://en.wikipedia.org/wiki/Space_Harmony). Well, it models two of them. An octahedron is not included, but this third basis can be visualized as formed by the centers of each face of the cube.) Try printing it in a transparent or translucent material!