-- Pixelinstanz Mehrfarbig mit eigenem Datentypen
data UglyColor = B | NB | G | QW | W
     deriving (Eq, Enum, Show)

instance Pixel UglyColor where
 toString W  = [' '] 
 toString QW = ['.'] 
 toString G  = [':'] 
 toString NB = ['+'] 
 toString B  = ['#']
 whitePixel  = W
 invertPixel pix = ...
 superimposePixel p1 p2 = ...