A surgeon retires from his long career as a specialist in circumcision.
Throughout his career, he has saved hundreds of foreskins as mementos and now wishes to turn them into a souvenir.
He takes his specimens to a leathersmith and asks him to make something out of them.
A week later the surgeon returns and the leathersmith presents him with a wallet.
"All those foreskins and you only made me a wallet?" exclaims the surgeon.
The leathersmith replies, "Yes, but if you stroke it, it becomes a briefcase."