Petrie Polygon
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 aRegular 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.See also Platonic Solid, Regular Polygon
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.
- Order (Modulo)
- Order (Ordinary Differential Equation)
- Order (Permutation)
- Order (Polynomial)
- Order Statistic
- Order (Vertex)
- Ordinal Number
- Ordinary Differential Equation
- Ordinary Differential Equation--First-Order
- Ordinary Differential Equation--First-Order Exact
- Ordinary Differential Equation Second-Order
- Ordinary Differential Equation--System with Constant Coefficients
- Ordinary Double Point
- Ordinary Line
- Ordinary Point
- Ordinate
- Ore Number
- Ore's Conjecture
- Ore's Theorem
- Orientable Surface
- Orientation (Plane Curve)
- Orientation-Preserving
- Orientation-Reversing
- Orientation (Vectors)
- Origami