Sam's rant involving poorly trained ground crews who didn't recognize the hand signal for "connect ground power" reminded me of all the times I've wished people on the ground or in other cockpits spoke sign language. I have learned some sign language in order to communicate a deaf relative, and it is infinitely frustrating when all the tools I need to transmit a message are literally at my fingertips, but the recipient doesn't have the information required to decode the message.
So I have to resort to more primitive forms of sign language. Pilots, imagine you were in the run-up area or in a traffic jam on the taxiways and another pilot, stuck her hands out of the cockpit displaying in sequence:
The splayed fingers of one hand, plus the thumb and finger of the other
The splayed fingers of one hand, plus just the thumb of the other
The fingertips of one hand all curled to touch the thumbtip, leaving a round gap through the middle of her fist
The third gesture repeated
If she repeated this sequence a few times, would you have any idea what she was indicating?