Section Quadrilateral_inter_dec_1.
Context `{TE:Tarski_euclidean}.

Lemma par_strict_cong_mid1 :
forall A B A' B',
Par_strict A B A' B' ->
Cong A B A' B' ->
(TS A A' B B'  /\ exists M,  Midpoint M A A' /\ Midpoint M B B') \/
(OS A A' B B' /\ exists M, Midpoint M A B' /\ Midpoint M B A').