Creating entire classes of things can also be done with Purity. For example, if someone feels like making the creation of life, or day and night.
The Purity cost here should be judged in a similar line. 5 Purity for a constant, world-spanning creation (life, day and night). 3 Purity for a wide-spread thing (thunderstorms, love, war), 1 Purity for a more specific thing (the singing of birds, shadows cast by moonlight, the love of children for their parents).
