https://github.com/davepinch/pinchy.cc/blob/master/content/topics/mathematics/shapes/octagon/octagon.md
Octagon (Wikipedia) In geometry, an octagon (from the Greek á˝ÎşĎÎŹÎłĎνον oktĂĄgĹnon, “eight angles”) is an eight-sided polygon or 8-gon.
