There was this construction worker, Brian, on the 3rd floor of this unfinished building. Brian needed a hand saw but was too lazy to go down and get it himself. So he tried to call to his fellow worker, Pat, on the ground to get it for him, but Pat could not hear a word he said. So Brian started to give a sign to Pat so that Pat could understand him.
So first Brian pointed to his eyes (meaning "I"), then pointed at his knees (meaning "need"), and moved his hand back and forth describing the movement of a hand saw.
Finally, Pat started shaking his head like he understood and dropped his pants and started to jack off.
Brian got pissed and ran down to the ground and started yelling at Pat, "You idiot, I was trying to say, 'I need a hand saw!'"
Pat replied, "I know, I was trying to tell you that "I'm coming. . ."