@irenes @PetraOleum One thing that falls at the intersection of both mathematics and programming us #AckermannFunctions. And from there, I discovered the recursive definitions of addition as repeated increments, multiplication as repeated addition, powers as repeated multiplication, etc. In highschool, I independently mapped out a whole recursive theory of arithmetic, building up from Peano's axioms, while other kids were out drinking and partying and making friends. Then in college, I learned that someone had already done the work, and it was called #HyperOperations. (This made me sad that I wasn't first, but glad that I wasn't alone.)

Cool trivia: 2 o 2 = 4 is always true, for any operation o in the entire infinite hierarchy from addition up.