Digon
polygon with 2 sides
In geometry, a digon is a polygon with two sides (edges) and two vertices. Its construction is degenerate in a Euclidean plane because either the two sides would coincide or one or both would have to be curved; however, it can be easily visualised in elliptic space.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Regular_digon_in_spherical_geometry.png/220px-Regular_digon_in_spherical_geometry.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/18/Waldseem%C3%BCller-Globus.jpg/220px-Waldseem%C3%BCller-Globus.jpg)
A regular digon has both angles equal and both sides equal and is represented by Schläfli symbol {2}. It may be constructed on a sphere as a pair of 180 degree arcs connecting antipodal points, when it forms a lune.
The digon is the simplest abstract polytope of rank 2.
A truncated digon, t{2} is a square, {4}. An alternated digon, h{2} is a monogon, {1}.