moveLater :: ListZip a -> Maybe (ListZip a)
moveLater (ListZip (late :< a') a early) =
    Just (ListZip late a' (a :> early))
moveLater :: ListZip a -> Maybe (ListZip a)
moveLater (ListZip (late :< a') a early) =
    Just (ListZip late a' (a :> early))
moveLater (ListZip (late :< a') a early) =
    Just (ListZip late a' (a :> early))