Broken Sign Blog
#126: Rail Pool / Masyu
6 November 2023This was originally going to be a co-op puzzle for two solvers. But after I had finished the puzzle, I realised that it would work much better as a hybrid puzzle for a single solver.
The co-op version felt a bit unbalanced, an important step in the puzzle was nastier than it needed to be, and I realised that there would be interesting additional logic from being able to see both rulesets. So I reworked the puzzle and was able to drop a lot of extraneous clues in the process.
Rules: Draw a non-intersecting loop through the centres of all cells. Some boldly outlined regions contain number clues. If a straight loop segment visits any cells of a clued region, its length must match one of these numbers. Each number must correspond to at least one such loop segment. Question marks represent any positive integer, but numbers cannot repeat within a region.
Variant: Masyu hybrid — The loop must turn on black circles and travel straight through the cells on either side. The loop must go straight through white circles, and turn in at least one of the cells on either side.