Paddy and Murphy are working on a building site.
Paddy says to Murphy "I'm gonna have the day off.
I'm gonna pretend I'm mad!"
He climbs up the rafters, hangs upside down and shouts

"I'M A LIGHT BULB! I'M A LIGHT BULB!"

Murphy watches in amazement!
The Foreman shouts "Paddy you're mad, go home"
So he leaves the site.
Murphy starts packing his kit up to leave as well.
"Where the hell are you going?" asks the Foreman.
"I can't work in the friggin' dark!" says Murphy.