Ltac CopR :=
 let tpoint := constr:(Tpoint) in
 let col := constr:(Col) in
 let cop := constr:(Coplanar) in
   assert_ncols; Cop_refl tpoint col cop.

Lemma image_id : forall A B T T', A<>B -> Col A B T -> Reflect T T' A B -> T = T'.