I really enjoyed learning about the so-called "combinatorial species" [1]. It is another good example of what you are describing. And this idea of differentiati

I really enjoyed learning about the so-called "combinatorial species" [1]. It is another good example of what you are describing. And this idea of differentiation as putting a hole, it just blows my mind every time i think about it. https://en.wikipedia.org/wiki/Combinatorial_species https://en.wikipedia.org/wiki/Combinatorial_species