brightness.average -r = color ->                 brightness.hypotenuse -r = color ->
  color.                                           color.
    round ((red +                                    round (sqrt ((red ** 2 +
            green +                                                green ** 2 +
            blue) / 3)                                             blue ** 2) / 3))
  ;                                                ;
_                                                _
  color : rgb                                      color : rgb
;                                                ;




