A piece of string walks into a bar, sits down and asks the bertender for a beer. The bartender says "I'm sorry but we don't serve your kind here, you're going to have to leave."
The string walks out, ties himself in a knot and tousles his "hair". He the walks back in a sits at the bar and says, "bartender, get me a beer."
The bartender asks "aren't you that string I just kicked out?"
The string replies "No, I'm a frayed knot."