Assertion: octagon's shape | /r/HasProperty | sided
Facets:
Source sentences:
text: Hi Phil, By mathematical definition, an octagon is an 8 sided 2-D shape.
text: An octagon is an 8 sided 2-D shape but in describing the 3-D "stop sign" shape (I drew one below that is thick enough that you can see the third dimension) mathematicians use the terms vertices, edges and faces.