A Spiro is a one-of-a-kind work of art created from a spirograph on the blockchain. It is created from an algorithm that produces mathematical roulette curves to generate art. Not all Spiros are created equally. An incredibly scarce number of Spiros will be minted as `rare`. The spirograph algorithm, your sequence of numbers, and a rarity curve will determine the rare-ness of your Spiro. In addition to the `rare` quality, these Spiros are distinguished by their `color`. Rare Spiros can come in a range of colors with some being more scarce than others. The time at which you mint can improve your chances to get a `rare` Spiro due to our rarity curve.