the three-dimensional einstein problem. Dual The dual polyhedron of the gyrobifastigium has 8 faces: 4 isosceles triangles, corresponding to the valence-3 vertices of the gyrobifastigium, and 4 parallelograms corresponding to the valence-4 equatorial vertices. See also Elongated gyrobifastigium Elongated octahedron References External links Johnson solids Space-filling polyhedra