Knock knock. Who's there? Fig

Fig who? Fig-ure it out yourself, I'm busy!

Knock knock. Who's there? Next.

Next who? Next time, just open the door, this isn't a surprise party.

Knock knock. Who's there? It's me.

It's me who? It's me, and I'm not here for a joke. I actually need to borrow a cup of sugar.

Knock knock. Who's there? Recursion.

Recursion who? Recursion who? Knock knock.