I remember there being something called Chirp (I think) that had a neat demo where you have two phones download the app, put the phones into aeroplane mode, and

I remember there being something called Chirp (I think) that had a neat demo where you have two phones download the app, put the phones into aeroplane mode, and then you can still make a box on the other phone move etc -- the implementation was ultrasonic sound I believe. I tried to find them again but it looks like they were bought out or equivalent by Sonos? [1] https://medium.com/chirp-io/data-over-sound-and-other-data-connectivity-technologies-41150139b3e4 https://medium.com/chirp-io/data-over-sound-and-other-data-c... [2] https://medium.com/chirp-io https://medium.com/chirp-io