Mildly suggestive test image
Used my Raspberry Pi Pico to make a 256x256 raster display that works with the XY mode of an analog scope. One of those things I knew how to do in theory but that was a few pleasant hours of wiring and debugging to make work for real.
The version with a Z output (for intensity) refreshes at 100Hz.
https://gist.github.com/insom/0e091bdb65e5abbd2fba68f8e7bebbd5
Mildly suggestive test image
Same, on a 1970's Tektronix scope. If anything the image is -more- stable on this one, although in person it wobbles like there is some stray capacitance somewhere.