Thursday, February 27, 2025

Genre Spotlight 16: Sea Serpent (Puzzles 249 and 250)

Sea Serpent is one of many snake genres, which can be a sticking point for many solvers.  (It's me, I'm many solvers.)  I don't actually know too much about the history of this type; I was able to find it in a 2003 24HPC round but am not sure if this is actually where the genre originates.  There are definitely aspects of this type which can be annoying, but overall I think it's friendlier than normal Snake.  Sea Serpent doesn't have a "no diagonal adjacency" rule, and it's possible to place clues which behave more locally.

Rules: Shade some cells to form a non-intersecting path which does not touch itself orthogonally. Circles mark the ends of the path. Clues cannot be shaded, and represent the total number of shaded cells that appear in the indicated directions.

(Example taken from WPC 2011.  Here the snake is represented by a path rather than by a group of shaded cells.) 


Monday, February 24, 2025

Genre Spotlight 15: Top Heavy (Puzzles 247 and 248)

I first saw Top Heavy a few years ago in a Puzzle Ramayan contest and thought it was cute.  At the time, I made a TomTom hybrid but never ended up constructing any vanillas.  I still believe that this type is cute -- it reminds me of Fuzuli in several ways -- but constructing one of these is not easy.

Rules: Place numbers from the range given outside the grid into some cells so that each row and column contains each number once. When two numbers touch vertically, the one on top must be larger.

                

Thursday, February 20, 2025

Genre Spotlight 14: Mine Shaft (Puzzles 245 and 246)

Mine Shaft was a genre localized on Puzzle Picnic back when the site was still live.  I can't seem to find it anywhere else, though I wouldn't be surprised if it's appeared multiple times and I never realized.  Mine Shaft is really a Snake variant of sorts; IMO "Hydra" would be an appropriate name for it.  I actually think it's superior to Snake in some ways.  While the less-restrictive structure of the solution means you generally need more clues to make puzzles unique, it also allows for more localized progress in areas, and I think there's more you can do with it overall.

Rules: Shade some cells in the grid to form a "mine shaft" -- that is, an orthogonally connected group of cells which contains no loops (not even 2ร—2s) and does not touch itself diagonally.  Given circles indicate all cells which are adjacent to exactly one other shaded cell.  Numbers above and next to the grid indicate the number of shaded cells in the corresponding row or column.