the knot

A string walks into a bar and ask the waiter for a beer. The waiter says, „I am sorry but we can’t serve strings here.“The string goes home, ties himself in a knot, and messes up his hair. He goes back to the bar about an hour later, sits down and says, „Waiter, give me a beer.“ The waiter says,“Hey aren’t you the string who came in here earlier.“The string replies, „No, I’m a fraid knot.“