never executed always true always false

    1 module HelVM.HelMA.Automata.Piet.Types.Lightness
    2   ( Lightness (..)
    3   , brightnessChange
    4   ) where
    5 
    6 import           HelVM.HelMA.Automata.Piet.Types.Extra
    7 
    8 brightnessChange ∷ Lightness → Lightness → Lightness
    9 brightnessChange = changeDiff 3
   10 
   11 data Lightness
   12   = Light
   13   | Normal
   14   | Dark
   15   deriving stock (Bounded, Enum, Eq, Ord, Read, Show)