Spiral print in Haskell

Spiral.hs

module Main where

transpose :: [[Int]] -> [[Int]]
transpose m =
  case m of 
    []      -> []
    ([]:_)  -> []
    x       -> (map head x) : transpose (map (drop 1) x)
 
spiralPrintShort :: [[Int]] -> [Int]
spiralPrintShort matrix =
  case matrix of
    [] -> []
    x:xs -> x ++ spiralPrintShort (reverse (transpose xs))

main :: IO ()
main = do
  print (spiralPrintShort [[1, 2, 3], [8, 9, 4], [7, 6, 5]])