The basic 3-dimensional element are the tetrahedron, quadrilateral pyramid, triangular prism, and hexahedron. In geometry, the great triakis octahedron is the dual of the stellated truncated hexahedron (U). Its dual polyhedron is the tetrakis hexahedron. A hexahedron (plural&colon; hexahedra) is any polyhedron with six faces. It shares its vertex arrangement with the stellated truncated hexahedron. A hexahedron, a topological cube, has 8 vertices, 12 edges, bounded by 6 quadrilateral faces. The cube can be seen as a rhombic hexahedron where the rhombi are squares. The cube can be seen as a rhombic hexahedron where the rhombi are also rectangles. In geometry, the truncated cube, or truncated hexahedron, is an Archimedean solid. Thus, the compound can be seen as a stellation of the tetrakis hexahedron. The cube is the only regular hexahedron and is one of the five Platonic solids. By contrast, a highly nonspherical solid, the hexahedron (cube) represents "earth". The name comes from the cubic (i.e. "hexahedron") structure of the kamacite crystal. Other degenerate forms of a hexahedron may also be represented. Polyhedral dice shaped like the tetrakis hexahedron are occasionally used by gamers.