scheck (n:ns) ((us, v, ws):xs) = ((us ++ [v] ++ ws) == (n:ns)) && (scheck (n:ns) xs)
scheck (n:ns) ((us, v, ws):xs) = ((us ++ [v] ++ ws) == (n:ns)) && (scheck (n:ns) xs)
scheck (n:ns) ((us, v, ws):xs) = ((us ++ [v] ++ ws) == (n:ns)) && (scheck (n:ns) xs)