Rainbow Vote

I'm building an interface for an event which utilises quadratic voting. Quadratic voting is a new concept to me, but the limit boundary - scarcity of voting resources - is what makes it pretty useful to gauge what people really favour imo. Basically, the more you vote for a particular item, the more it is going to cost. First vote costs 1, second vote for the same item costs 3, and so on, based on this formula:

Cost to the voter = (Number of votes)^2

Why rainbow? Cos it represents variety in thoughts and sentiments! Though, someone in my team says the norm about the word "rainbow" = LGBTQ. Didn't know that.