User blog comment:Bubby3/BM1 is weaker than expected./@comment-30754445-20180326085136

Whoa! What a surprising find.

What's particularly devistating is that this sequence is reachable from (0,0)(1,1)(2,2)(3,3). It's not just a rogue string.The system really is broken at that point.

Let this be a lesson to all, regarding the importance of carefully and rigorously proving every statement you make.