Two Irishmen went into a pub and after ordering two pints of Guinness, took some sandwiches out of their pockets and proceded to eat them.
Seeing what they were doing, the barman walked over to their table.
“You can’t eat your own sandwiches in here”, complained the barman.
So, the two Irishmen passed their sandwiches across the table to each other.
The barman was stumped.
Image used under a Collective Commns License from https://fr.wikipedia.org/wiki/Fichier:British_Rail_sandwich_01.jpg