Perhaps the lesson there is, just because you can wedge meaning in doesn't mean you should. The final method of communication is flashing. Flashing red is like a stop sign. Flashing yellow, proceed with caution. I don't think flashing green is ever used or what it could mean.
Most flashing lights are there to draw attention.
Emergency vehicles, gaudy advertisments, navigation lights. Flashing signals are deliberately jarring. They're also rarely used in combination with the normal signals. This is very important. The normal confusion associated with a break in the pattern isn't there since the normal pattern is totally absent.