wTape :: t      -- ^ The element to write
      -> Tape t -- ^ The tape
      -> Tape t -- ^ The modified tape
wTape b (Tape l _ r) = Tape l b r
wTape :: t      -- ^ The element to write
      -> Tape t -- ^ The tape
      -> Tape t
wTape b (Tape l _ r) = Tape l b r
wTape b (Tape l _ r) = Tape l b r