[philipfweiss]

Four colors is sufficient for a planar graph, but insufficient for a general graph. A planar graph is any graph where the edges can be drawn in such a way that they only intersect at the endpoints (there is a more formal algebraic definition but that helps with the intuition).

[dylanfw]

Thank you! That makes complete sense when I consider the 4 color example of a world map. I didn't even consider that most graphs would have "overlapping borders" on such a map.

An extra thank you for apparently creating a new account to assist me. (I think that's what the green username indicates, at least).