Star Polyhedron
A star polyhedron represents a generalisation of the classical definition of a polyhedron, in that the faces are now allowed to intersect each other at places other than edges, and the faces may be star polygons.
There are four regular star polyhedra, know as the Kepler–Poinsot Star Polyhedra. The set of semi-regular star polyhedra is know collectively as the Stellated Archimedeans.
Regular and semi-refular star polyhera have fractional values in their vertex symbols.