edges, shapes, and borders... or all of the above :p
There are many:prismpentangleparabolapentagramparallelepipedparallelogrampentadecagonplanepolygonpyramid
pentagon!!
Pentagon paralellagram
a tripod :P
well weathering is weathering. so it shapes the earth all the the time. :P
7 Sides on a Twenty Pence Piece
clearly not squares :P
Polygon
Plastics
Maybe only a circle and a oval. :P
polygon pentagon parallellagram pyramid