We're roughly following the colours of the rainbow:
Red-Orange-Yellow-Green-Blue-Purple and throwing in Black and White.
Occassionally one of us will get the itch for a different colour and throw in pink, silver, brown....whatever.
It really doesn't matter. We do roughly head back to the rainbow so that we don't get 7 reds in a row....Hmmm..... Now I've got me thinking...which is always a bad thing!