Section PARALLEL_SUPERIMPOSED.

Lemma EquiDirectedLineBCollinear : forall A : Point, forall F F' : Figure, forall D : Line F, forall D' : Line F',
EquiDirected (LineA F D) (LineB F D) (LineA F' D') (LineB F' D') ->
F A ->
F' A ->
LineB F D <> A ->
F' (LineB F D).