 For example, the 5 Platonic solids have 4-, 6-, and 10-sided regular skew polygons, as seen in these orthogonal projections with red edges around the projective envelope.The tetrahedron and octahedron include all the vertices in the zig-zag skew polygon and can be seen as a digonal and a triangular antiprisms respectively.The regular skew polyhedron have regular faces, and regular skew polygon vertex figures.