Icosahedron
Great icosahedron

The great icosahedron is one of the four regular star Kepler-Poinsot polyhedra. Its Schläfli symbol is {3, 5 / 2 }. Like the convex form, it also has 20 equilateral triangle faces, but its vertex figure is a pentagram rather than a pentagon, leading to geometrically intersecting faces. The intersections of the triangles do not represent new edges.

Its dual polyhedron is the great stellated dodecahedron { 5 / 2, 3}, having three regular star pentagonal faces around each vertex.
startend:quotation, oulipo:avoid_letter[e], language:response_language[English]