So there is this crazy theory going around on Twitter... FreeKeshaLuke tweeted this: 'When we reach the end of the rainbow, will there be a pot of gold".
People are assuming that when she goes through all the 7 colors of the rainbow, we'll finally reach the ''pot of gold'', meaning her new single -> Stay Gold..
I doubt it's true but it's really well thought if you think about it

In that case we're missing 4 colors: green, yellow, orange and red.