Equiprojective polyhedra

Template:Short description In mathematics, a convex polyhedron is defined to be $k$-equiprojective if every orthogonal projection of the polygon onto a plane, in a direction not parallel to a face of the polyhedron, forms a $k$-gon. For example, a cube is 6-equiprojective: every projection not parallel to a face forms a hexagon, More generally, every prism over a convex $k$ is $(k+2)$-equiprojective.Template:R Zonohedra are also equiprojective.Template:R Hasan and his colleagues later found more equiprojective polyhedra by truncating equally the tetrahedron and three other Johnson solids.Template:R

Template:Harvtxt shows there is an $O(n\log n)$ time algorithm to determine whether a given polyhedron is equiprojective.Template:R