@ØrjanJohansen Hmm, okay, I think I can see how to do that (the rational numbers are embedded in the Acc!! code, and the accumulator simply stores the instruction pointer). It would make for a pretty long expression, indexing into a list of rational numbers! Be that as it may, I have come up with a translation from a Brainbool variant with 2-level nesting that I think should work. Will clean it up and post on Esolangs whenever I have time.