Definition CongruentStrictTriangles (A B C A' B' C' : Point) :=
	CongruentTriangles A B C A' B' C' /\
	~Collinear A B C.

Lemma ClockwiseEq : forall A B C D : Point, Clockwise A B C -> Collinear A B D -> Collinear B C D -> B = D.