“So what you’re saying is that the statement at the top of this paper is for me to prove using these equations?” I nod. “OK, but I don’t get what f and g actually do. That’s making like no sense.” [scribbles a bunch of notes on a board and, over the course of five minutes, gets to why mathematicians decided to write “f of g” with a dot but not explain how it actually works] “OK, that was really good.”…