There was this construction worker on the 3rd floor of this unfinished building. He needed a hand saw, but was too lazy to go down and get it himself, so he tried to call his fellow worker on the ground to get it for him, but this guy could not hear a word he said. So he started to give a sign so the guy on the ground could understand him.
First he pointed at 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, the guy on the ground started nodding his head like he understood and dropped his pants and started to jerk off.
The guy on the 3rd floor got pissed-off and ran down to the ground and started yelling at this guy, "You, idiot! I was trying to tell you I needed a hand saw."
The other guy replied, "I know! I was trying to tell you that I was coming."