Uhm author here. Not sure why this tweet is on Hacker News, as it is just a non-technical "blog post". But I've posted a follow-up today with some code and details, if you're curious:
Only thing I could read (don't understand any of this otherwise) was that you take input pairs and you give python function to generate that output. Does that mean that many math etc problems can be just solved? What kind of python code will it generate to return primes?
It will just return the smallest function that passes your tests.
It works by enumerating ALL possible functions and running them. Obviously, that naive approach is exponential, so, the entire point is whether we can apply some clever tricks (based on optimal evaluators) to make this search "slightly less intractable".
So, to answer your question directly: if you asked it to design a prime number generator, if it found anything at all, it would probably be a simple, slow trial-and-error algorithm, or something in these lines.