I found some similar answer but I don't understand how to derive the answer.
if I colour my hexagons r(ed), g(reen), b(lue), then obviously the six hexagons
(r, r, r, g, g, b)
(r, r, g, g, b, r)
(r, g, g, b, r, r)
etc.
are different, but all equivalent. Whereas:
(r, r, r, r, r, r)
is the only...