I want to make something like the following image in tikz:
To be able to do this, I would need to, essentially double nest nodes. I saw this post about nesting nodes: Nested TikZ nodes. The solution in that post uses matrices, which, according to: In TikZ, is it possible to nest matrices? is not possible. Also, there is the arrows, not sure where to even start with that, that is probably gonna depend on the implementation of the double nested nodes I guess.
So, I was wondering if it is possible to create that image, or something similar through tikz.