How to make a Harmonograph

Unfortunately the video doesn't work because I have used the wrong format. Does anyone know where to find information, which format to use on DTube?

Hey, as you can read here: https://steemit.com/steemit/@musicbox/how-to-dtube-having-problems-login-in-dont-know-how-to-use-it
DTube does NOT reencode your videos. It stores and plays them in the format you upload them.
A bit downwards in the comments you can see some suggestions,
e.g. upload your videos in MP4 or WebM.

Hope this helps!

I watched the video on the discord channel. Great and interesting. I can see your engineering background coming through in the design.