Having read the paper (and having begun replicating the results in Ruby), I _think_ the novelty here is that 1) the "world" is seeded with a normal distribution

Having read the paper (and having begun replicating the results in Ruby), I _think_ the novelty here is that 1) the "world" is seeded with a normal distribution of random (though valid BF) noise and 2) there are no world rules that should incentivize replicators. The rules of engagement are the sharing of a resources (the "tape") between two programs and the VM executing BFF. My intuition would think we'd end up with the same distribution of randomness in most cases, however, the researches consistently discovered dominant replicators. I'm excited to read more about Tierra and others prior art to understand if observation has precedent. My introduction to all of this is Shiffman's Nature of Code, so I am not familiar with the literature. The other new research introduced in the paper was the way the BFF VM and "tapes" were observed. By using entropy and compressibility, the authors observe complexity as a heuristic for presence of self-replication in the "primordial soup" simulation.