Octadecagon

The octadecagon is a polygon with 18 sides. A regular octadecagon has equal sides and equal angles.

Stellations

 * 2-octadecagram (compound of 2 enneagons)
 * 3-octadecagram (compound of 3 hexagons)
 * 4-octadecagram (compound of 2 enneagrams)
 * 5-octadecagram
 * 6-octadecagram (compound of 6 triangles)
 * 7-octadecagram
 * 8-octadecagram (compound of 2 great enneagrams)