I'm not the creator of that magnificent piece of programmatical art. But I can take a stab at this. As long as the languages are Turing complete it is possible.

Any Turing machine can simulate any other Turing machine so once you step up to that level the challenge is keeping your head through the maze of nuances between many of those languages. I think the logic behind it goes something like this, if a language is complete (eg in the Gödel sense) then you can have it produce things that are nonsense in its own language.

Anyways I would expect the bulk of the work to be making those incremental step of going from each language to the next. In terms of data shape, I am thinking a linked list. So the final step is to call them all in a nested fashion, bootstrapping each up onto the top of that stack as you go.