I’m flat. I started as a mark or dot and expanded myself. I’m thought of as much wider than a line. My purpose is to cover area, I’m usually the same boring value throughout, as in the apple above. And, like line–I am foremost a concept.
A caution: The perception of me as plane totally depends on scale. A person looking at a hose on the ground perceives me as linear, but an ant crawling on the hose would see me as planar.
I have some talent: I can bend or fold. I can have torn or deckled edges– smooth edges or jaggy edges. I am especially known to make nice silhouette portraits and paper airplanes.
Sometimes I am the stage, or the background upon which a line acts. If line is applied to me, it may be influenced by the surface I’m representing at the moment–and it also will depend upon which tool and medium is used to make the line.
Plane is a way to describe things.