concat :: [ByteString] -> ByteString

{-# LANGUAGE ExistentialQuantification #-}

data Showable = forall a. Show a => Pack a
instance Show Showable where
    show (Pack a)=show a

showableList :: [Showable]
showableList = [Pack 1, Pack "Yolo", Pack 5.2, Pack (3, 4), Pack ["A", "B", "C"], Pack 'c']

main=print showableList