@neauoire I have never ran the BITPICT software (I did a few homebrew implementations hehe), but as far as I understood is a cellular automata like engine with variable neighborhood/event window and all the computation is done through pixel rewrites. I am not super familiar with Oberon, but this article discuss a few ideas around building interfaces with pixel rewrite, I guess it could be generalized as symbol/sign/tile rewrites?

I am following your string rewriting exploratiom very excited to see what is going to come out of it :B