Hint Resolve cong_left_commutativity cong_right_commutativity : sTarski.

(* Specifications: *)
Lemma cong_trivial_identity : forall A B : Point, Cong A A B B.
Hint Resolve cong_trivial_identity : Tarski.
Lemma cong_reverse_identity : forall A C D, Cong A A C D -> C=D.
Proof with eTarski.