In most modern programming languages including Go, it's possible for a function to call itself recursively. It's such a mainstream technique that we've come to take it for granted.

But what if functions couldn't call themselves?

There's a branch of mathematics called Combinatorics which answers just this question, and in this session we're going to study that answer and see what it can teach us.

When we're finished you might never look at Go - or programming - the same way ever again.