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? Isadore.

Isadore who? Isadore a lock on this door, or is it just glued shut?

Knock knock. Who's there? Recursion.

Recursion who? Recursion who? Knock knock.

Knock knock. Who's there? A man with a

manuscript for a knock-knock joke, but he's struggling to come up with a decent punchline, and honestly, it's just getting a bit meta at this point.