Sub-list of the list of polytopes
Self-intersecting polygons , crossed polygons , or self-crossing polygons are polygons some of whose edges cross each other. They contrast with simple polygons , whose edges never cross.
Some types of self-intersecting polygons are:
the crossed quadrilateral , with four edges
the antiparallelogram , a crossed quadrilateral with alternate edges of equal length
the crossed rectangle , an antiparallelogram whose edges are two opposite sides and the two diagonals of a rectangle , hence having two edges parallel
Star polygons
pentagram , with five edges
hexagram , with six edges
heptagram , with seven edges
octagram , with eight edges
enneagram or nonagram, with nine edges
decagram , with ten edges
hendecagram , with eleven edges
dodecagram , with twelve edges
icositetragram , with twenty four edges
257-gram , with two hundred and fifty seven edges