Ok. I'm in the countryside now but when I get back to Ulaanbaatar a few days later I'll look into it.

Ok I tracked down the problem. I was neglecting to update a variable that needed updating. It was only causing an error in 1 out of 1000 games, but now it should be zero.

However ... in fixing that problem I seem to have created a new problem. I'm going for massage now, but when I return I'll get back on it.

Fractal was already a massive effort before this nonsense.

I'll keep you posted.

Ok, got it. I realized during my massage that there had to be a typo. The only thing I had changed, other than fixing the bug, was to rename some variables to be more descriptive. Sure enough, after like 10 seconds of investigation, it jumped out at me. There was a $u_su where there should have been a $u_sub.

While fixing the win detection bug (by far the most difficult bug I've fixed so far), I also streamlined the win detection function to be much more efficient. The interface was already pretty snappy, but now it should be lightning fast.

So, after this long Fractal journey, the program should finally be in pretty good shape. From now on, I don't want to hear any more complaints !!

(joking)

Of course, if there are any problems, let me know.