Hah... that's not much of a vandal

But yeah, I was thinking of adding "On a Euclidian plane," but it seemed too wordy. From the wikipedia page:
"This can be done on a sphere, and not on a flat surface. Note that the later discovery of non-Euclidean geometry does not resolve this question; for one might as well ask, "If given the axioms of Riemannian geometry, can an omnipotent being create a triangle whose angles do not add up to more than 180 degrees?" In either case, the real question is whether or not an omnipotent being would have the ability to evade the consequences which follow logically from a system of axioms that the being created."