Require Export GeoCoq.Elements.OriginalProofs.lemma_collinear4.
Section Euclid.
Context `{Ax1:euclidean_neutral_ruler_compass}.

Lemma lemma_twolines2 :
forall A B C D P Q,
neq A B -> neq C D -> Col P A B -> Col P C D -> Col Q A B -> Col Q C D -> ~ (Col A C D /\ Col B C D) ->
eq P Q.