docs: def colourblind(i):
      '''
          colour pallete from http://tableaufriction.blogspot.ro/
          allegedly suitable for colour-blind folk
  
          SJ
      '''
  
      rawRGBs = [(162,200,236),
                 (255,128,14),
                 (171,171,171),
                 (95,158,209),
                 (89,89,89),
                 (0,107,164),
                 (255,188,121),
                 (207,207,207),
                 (200,82,0),
                 (137,137,137)]
  
      scaledRGBs = []
      for r in rawRGBs:
          scaledRGBs.append((old_div(r[0],255.),old_div(r[1],255.),old_div(r[2],255.)))
  
      idx = sc.mod(i,len(scaledRGBs))
      return scaledRGBs[idx]