Three pieces of string, one with a knot in, were chatting outside a pub.

String 1 said "I bet I can get served with a pint of beer in there".

Strings 2 & 3 were a bit sceptical.

String 1 went into the pub and said to the landlord "Pint of beer please".

"Certainly" said the landlord and served him the pint of beer.

String 2 thought he would try the same trick so he went into the pub next.

"Pint of beer please" he said.

"Certainly" said the landlord and served him the pint of beer.

String 3 thought 'if they can do it, so can I' so he marched into the pub.

"Pint of beer please" he said to the landlord.

The landlord looked at him and said "Sorry, I can't serve you with a pint of beer".

String 3 was crushed and couldn't understand why Strings 1 & 2 had got served and he couldn't.

So he said to the landlord "You served Strings 1 & 2 with a pint of beer but you won't serve me?"

The landlord looked at him pityingly and said "Fraid not, we don't serve string with untidy knots in".