proposition: Theorem make_listto4irA c l1 l2 ll1 ll2 : to4it _ make_list l1 l2 (ll1++ll2) c = ll1 ++ to4it _ make_list l1 l2 ll2 c.
proof: Proof. case c; unfold to4it; auto with datatypes. intros cc1 cc2 cc3; repeat rewrite make_listto3irA; auto. Qed.
imports: PrimInt63 Cyclic63 List BasicRubik