After conferring about this for a while, the two nuns decide to lock the door of the room, strip off their habits, and paint in the nude. In the middle of the project, they hear a knock at the door.
"Who is it?", calls one of the nuns.
"Blind man," replies a voice from the other side of the door.
The two nuns look at each other and shrugged, and, deciding that no harm can come from letting a blind man into the room, they opened the door.
"Nice tits," said the man, "Where do you want these blinds?"