I recommend spending an evening reading about color theory and human perception and CIE 1931 on Wikipedia. http://en.wikipedia.org/wiki/CIE_1931_color_space ht

I recommend spending an evening reading about color theory and human perception and CIE 1931 on Wikipedia. http://en.wikipedia.org/wiki/CIE_1931_color_space http://en.wikipedia.org/wiki/CIE_1931_color_space In short, the "cowlick" is the range of human color perception, and no triangle made of linear-combinations of three visible primaries can cover the entire cowlick.