(* Lemma t2_8 : forall A B C D E : Tpoint, Bet A B C -> Bet D B E -> Cong A B D B -> Cong B C B E -> Cong A E C D. *)

Lemma out_cong_cong : forall B A A0 E D D0,
Out B A A0 -> Out E D D0 ->
Cong B A E D -> Cong B A0 E D0 ->
Cong A A0 D D0.