Knock knock. Who's there? Harry.

Harry who? Harry up and open the door!

Knock knock. Who's there? Blink.

Blink who? Blink and you'll miss this utterly tear-able pun about eye-popping humor, so prepare your ocular orb for an optic shock!

Knock knock. Who's there? Maple.

Maple who? Maple syrup to talk to someone, I'm feeling a little drained.

Knock knock. Who's there? Wheat

Wheat who? Wheat you waiting for, let me in