@neauoire I had a fever dream about a computer that could only run one piece of software which was self modifying and the source had to be twisted in real time to do what you needed. The program was fixed length, and always had to stay that length, so you could only overwrite bytes.
I feel like you might make this real.
@jameschip wow, that sounds like Uxn, a program is always 64kb.
https://wiki.xxiivv.com/site/uxntal_doors.html