As retold by Bruce Lowitt

A man walks into the U.S. Patent Office.

"I'd like to patent this," he says, taking out a wallet.

"Sir," the bureaucrat says, "wallets have been around for centuries."

"Yeah, but I'm a mohel. I do circumcisions."

"So?"

"So this wallet is made from mine clippings."

"But it's still a wallet, right?"

"Yeah, but this wallet, you stroke it a few times and it turns into a briefcase."