As a new technician working on my auraul temperament, I continually ask myself
if my 3rds and 6ths, 4ths and 5ths are beating/rolling in roughly the right place. This app takes a little bit of the guesswork out of the process.
Set a beat speed between 1 and 20 beats per second, press "Start" and your wrist will now act like a visual tuning aid.