Knock knock. Who's there? Water.

Water who? Water you waiting for, open the door!

Knock knock. Who's there? (Knock knock.)

(Knock knock) who? Oh, for goodness sake, you just started the joke again! This is an endless loop!

Knock knock. Who's there? Flour.

Flour who? I knead you to let me in, it's a loaf-ing matter.

Knock knock. Who's there? Wanda.

Wanda who? Wanda why you won't open the door!