I've heard a trick that acrobatic flight squads like the Blue Angels use when coming into really tight formations is each pilot hums at a specific frequency/ton

I've heard a trick that acrobatic flight squads like the Blue Angels use when coming into really tight formations is each pilot hums at a specific frequency/tone. By varying their pitch up or down, they can signal to the other pilots what they're about to do, kinda like an audio turn signal. And because each pilot is humming at a different frequency, everyone in the squad can be communicating at the same time -- in the same way you can pick out different instruments in a song, our ears can separate different simultaneous humming at different frequencies. Not sure this is what the author meant in the first section when he wrote: > I suspect you can push the user into a conversational skeuomorphism if you think that’s best, and the user will play along, but it’s no more right than another metaphor. It’s a question of quality of interaction, not ease or familiarity. ...but it's an interesting example of non-conversational multiplexed voice communication.