For some reason this makes me imagine an alternate history sci-fi universe where Pythagoras (famous for his love of fractions) invents FRACTRAN. Then Archimedes builds a mechanical computer to execute those programs, and one of the successors of Alexander The Great puts the computer to use in warfare and conquers the world. Science is accelerated so that nuclear physics are invented by the time Jesus is born...
Fractran is a wild ride as far as esolangs go. At first it seems impossible to build any programs in it, then you learn a few tricks like special primes for control flow and abstracting up to an imperative language. Being able to capture these abstractions in Lisp shows how powerful features like macros and homoiconicity are.
It carries over to statically typed languages too. I translated the blog post to Haskell (using the tagless-final design pattern), allowing one to represent Fractran programs as values, pretty print them and pass them through an optimizer[0]
