RYGCBM hexagon

Here we see the hexagonal structure of the RGB color system, as described on a flat hexagonal plane by the HSV coordinate space at V=1.

Human perception of color is tied to idiosyncracies in the hominid nervous system, and conceivably tetrachromats and pentachromats perceive far more complex spectra of colors that cannot be modeled on hexagonal principles at all. It may be, however, that the hexagonality of the human color spectrum is linked to some sort of innate neurological tendency towards hexagonal information processing. Indeed, it could be that the hexagonality of our color spectrum mirrors less-obvious hexagonal symmetries elsewhere in the subtle mechanisms by which our nervous systems structure reality.