Logic Masters Deutschland e.V.

Nerodia (Aquarium + Snake)

(Eingestellt am 28. Februar 2022, 21:48 Uhr von Nordy)

This puzzle is the result of a collaboration with my buddy Pokitchayng. He does not have an account here (yet), but you can find him on the CTC Discord.

Assignment #1: Welcome, new recruit! You have been assigned to an enclosure with our newest semi-aquatic snake, Mr. Slithers. This particular reptile has a knack for hiding—in fact, you will have to work out exactly where he is in the habitat. We have provided you with a blank diagram of the enclosure. Please notate the current water levels and use them to track the location of Mr. Slithers.

Rules: This puzzle combines aquarium and snake rules.


  • Each bordered region is an aquarium, and cells must be shaded blue (water) and green (air).
  • Within a region, any cells that are in the same row must be the same color.
  • When a row of cells within a region is filled with water, all cells below that row in the region must also be filled with water.
  • Regions may be entirely water or entirely air.


  • Place circles in cells (or use another technique) to form a single 1-cell wide snake.
  • The snake cannot touch itself orthogonally or diagonally.
  • The two ends of the snake are marked by black circles.
  • No set of 3 consecutive snake cells may be all water or all air. For example, if the snake passes through two water cells in a row, then the next cell on the snake’s path must be air (Mr. Slithers has to breathe!)
  • Every region must contain at least two snake cells.

External Clues:

  • Numbers outside the grid indicate the number of water cells and/or the number of snake cells in the corresponding row or column (a number can signify the amount of water cells, snake cells, or both).

Example: An example puzzle and solution are included for your reference. We found that Penpa+ with circles and lines for the snake was the most user-friendly.

Here is the main puzzle. Good luck!

  • Penpa+ (Shade air cells green and draw a green line through the snake for answer check)
  • CTC
  • F-Puzzles

If you get stuck, rereading the rules can be helpful!

Lösungscode: Starting from the top row, the number of snake cells in each row (9 digits) followed by the number of water cells in each row (another 9 digits)

Zuletzt geändert am 1. März 2022, 02:59 Uhr

Gelöst von Jesper, Dandelo, r45, jessica6, misko, marcmees, Lara Croft, Statistica, DVFrank, Luigi, SudokuExplorer, MariaL, BenceJoful, CJK, moeve, Dina, Mark Sweep, MagnusJosefsson, Joe Average, thefallenrat, codewizard, rimodech, flo_310, ildiko
Komplette Liste


am 12. April 2022, 10:34 Uhr von Hausigel_mod
Labels/Tags changed

am 4. April 2022, 14:53 Uhr von thefallenrat
The hardest working snake on the grid!

am 2. März 2022, 16:31 Uhr von Luigi
What a fantastic puzzle!!

Thank you very much for sharing it with us!

am 2. März 2022, 14:18 Uhr von DVFrank
Very nice! :^)

am 2. März 2022, 07:59 Uhr von Statistica
Sehr hübsch. Danke!

am 1. März 2022, 19:30 Uhr von Dandelo
The old discussion about "snakes and loops touching itself" ...

In the forum you find a long discussion (in German, but Google translator will help).


Zuletzt geändert am 4. März 2022, 00:31 Uhr

am 1. März 2022, 14:37 Uhr von SudokuExplorer
Btw, the example puzzle is not unique: https://tinyurl.com/n9z9xvsr

—Nordy: Ah, perhaps the “path” tag is confusing here? The path in this puzzle has to behave like a traditional snake (not like the loop in a castle puzzle, for example). The solution you provided is a snake that “touches itself”. I am now very intrigued about an aquarium puzzle with that type of pathing now though…

SE: I completely forgot about the snake rules, but could still make quite a few interesting deductions in the example puzzle. I'm glad my failure to understand all the rules has actually inspired you to think about another puzzle. I look forward to it! :-)

am 1. März 2022, 02:59 Uhr von Nordy
Minor formatting fix

am 28. Februar 2022, 22:50 Uhr von Jesper
Good fun, thanks!

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