That’s cool. There is a nice demo at the start of this video <a href="https://youtu.be/LmISP_fAAws" rel="nofollow">https://youtu.be/LmISP_fAAws</a>
Any reason a belt with holes couldn't replace the disk with holes for a more compact and rectangular viewing surface? Should be easy enough to test with a belt sander.<p>The closest thing from the time was mirror drums but those don't sound too similar, and they had mirrors for some reason.