Thanks, had a read and I think I understand approximately. I am still wondering whether biological systems should count as cyclic in this sense too? I think that they seem to, in the returning-to-the-same-state thing, at least across the generations, and even in regular metabolism in some sense - but the law doesn't (intuitively) seem to apply in the biology/evolution case.. it doesn't just diffuse, it can go on in pretty much precisely the same pattern for billions of years it seems? I guess I am probably ignoring something huge about this (like the Sun!?)