End T11_1.
Section T11_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma conga_ex_cong3 : forall A B C A' B' C',
CongA A B C A' B' C' -> exists AA, exists CC, Out B A AA -> Out B C CC -> Cong_3 AA B CC A' B' C'.