loopy gameplay

playing some slitherlink/loopy using [this implementation](https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/loopy.html) by simon tatham. this is what gameplay looks like once you have a pretty large repertoire of theorems figured out, and have practice in visualizing the constraints; a newbie would be hiding more edges, and wouldn't know how to proceed except by guesswork in many of these situations. there were a handful of guesses in this video, but most of the moves, even the ones that might seem random, were actually deductions. most of the theorems used have been practiced to the point where they can be used seamlessly, without conscious effort needed to remember and apply them. these games were all on the "7x7 squares - hard" difficulty preset. if you're new to this game, try the easy difficulty on a low board size (you can go down to 3x3 in the "custom" board type).