Broken Sign Blog
#022: Rail Pool (Cipher)
17 June 2022I had wanted to make a Rail Pool cipher that also spells the genre name for weeks, but just couldn’t get anything to work in a way I liked. Once it occurred to me that I could spell it out diagonally, things fell into place pretty quickly and I think the resulting logic is quite fun, too.
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: Cipher — Each letter represents a different positive integer which needs to be determined.