First off, thanks a lot for posting this and you did a great job with it! It was fun to play around with and it obviously inspired me enough to dig into the cod

First off, thanks a lot for posting this and you did a great job with it! It was fun to play around with and it obviously inspired me enough to dig into the code and try my own variation. You're right about them not matching exactly; I did it in a hurry and wasn't looking closely enough. I removed that incorrect statement (though it does seem to generally outperform the simulated annealing). The tie breaking for pairs with equal differences and the parity of the image is essentially random. It is deterministic in the code, because it won't replace a candidate unless it's strictly better, but it's totally arbitrary which is found first.