proposition: Lemma find_one_correct_aux g : size g = hw * hw -> if find_one g is some g1 then g1 \in find_all g else find_all g == [::].
proof: Proof. move=> Hs; rewrite /find_one /find_all. case: gen_init_state (gen_init_state_correct Hs) => // st _. apply find_one_aux_correct. Qed.
imports: mathcomp(all_ssreflect) mathcomp(zify)