A skew Polygon such that every two consecutive sides (but no three) belong to a face of a regular Polyhedron.
Every finite Polyhedron can be orthogonally projected onto a plane in such a way that one Petrie polygon becomes a
Regular Polygon with the remainder of the projection interior to it. The Petrie polygon of the Polyhedron
has sides, where

The Petrie polygons shown above correspond to the Platonic Solids.

**References**

Ball, W. W. R. and Coxeter, H. S. M. *Mathematical Recreations and Essays, 13th ed.* New York: Dover, p. 135, 1987.

Coxeter, H. S. M. ``Petrie Polygons.'' §2.6 in *Regular Polytopes, 3rd ed.* New York: Dover, pp.24-25, 1973.

© 1996-9

1999-05-26