The 3 strings and the bartender.

3 strings walk into a bar. First one orders a drink. Bartender says we don’t serve your kind in here. So the second string ties itself into a bow and proceeds to order a drink. Nope, says the bartender, you’re a string. Third string ties itself into a knot and frays each end. Orders a drink. Bartender eyes the string up and down and says, aren’t you a string? And the string says, frayed knot!