A string walks into a bar and orders a beer. The bartender says, "Sorry pal, we don't serve strings here."
So the string walks outside, ties himself in a loop and messes up the top of his hair. He walks back into the bar and orders a beer.
The bartender squints at him and says, "Hey, aren't you a string?"
The string says, "Nope, I'm a frayed knot."