Piston aircraft still use it. Which makes it doubly annoying when some tit in a cesna decides to circle around town at 1000’.
Not just making a noise, also cropdusting with TEL.
Piston aircraft still use it. Which makes it doubly annoying when some tit in a cesna decides to circle around town at 1000’.
Not just making a noise, also cropdusting with TEL.
While not strictly a QR code, I always liked that the Dolby Digital data between perforations on a film strip had a tiny Dolby logo at the centre.
https://en.wikipedia.org/wiki/Sound-on-film#/media/File:35mm_film_audio_macro.jpg