I found that sound was completely broken in MAME, in the extremely loud kind of way. Not a fun experience. I’d like to look into it more so that I can file a bug report, but I don’t yet know where the blame lies.
Every other program that I use seems to work fine so far.
This might be the first time I’ve ever seen something productive happen in the Phoronix forums. I love that place. Go to any topic with more than about a dozen posts and it’s almost guaranteed to be a flame war. Genuinely one of the funniest places on the Internet.
Check out this one. It took like three posts!
Here’s one I know. Creates aesthetic wavy things.
https://tanck.nl/wallpaper/
It is an HTML/JS pair, so it would require some wrangling to get it to write to a file instead of an HTML canvas. Though it looks like someone translated it to Python with file output here. (I have not tested this.)