Castle Wall Delta #2 (15x15)
(Published on 1. June 2021, 08:38 by Jesper)
Rules
Draw a single closed loop (without intersections or crossings) passing through some empty cells in the grid.
The loop shall consist of horizontal and vertical segments connecting the centers of cells.
Cells that are colored and/or have heavy borders cannot be part of the loop:
- Black cells must be outside the loop
- White cells with heavy borders must be inside the loop
- Grey cells may be inside or outside the loop
The loop has an orientation (to be determined during the solve).
A number in a clue cell indicates the total number of steps made towards that cell minus the total number of steps made away from the cell, when completing a lap of the loop. Only steps within the row or column of the clue cell count.
Example:
The puzzle follows:
Penpa+: Castle Wall Delta #2 (15x15)
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Solution code: For every row (from top to bottom), the number of turns of the loop
Comments
on 9. October 2023, 10:52 by Niverio
Remarkable. A very memorable puzzling journey. Thanks a lot for this masterpiece!
on 30. September 2023, 23:32 by zzw
Absolutely gorgeous puzzle! Builds very well upon #1. And something about this type of puzzle makes it feel very satisfying every time you find a new loop segment... Thank you!
on 30. September 2023, 09:32 by wisty
This was amazing!!! Oh my gosh! The first one was very difficult at first but I love this style of puzzle and though the deductions are more thorough in this one I overall felt a lot more comfortable with it, especially when I decided to use numbers to notate sides of the blocks with the possible sums they could have. The break-in is a ton of fun, and the mid-solve is very elegant - it's such a clear solve path with rewarding deductions that teach intuition. I'm with Myxo and The Book Wyrm - it's a long one due to scanning and counting, but nothing in this is monstrously hard or anything. I loved every minute of it! Thank you SO SO much for sharing this series!
on 24. September 2023, 16:55 by The Book Wyrm
Well, that was crazy. A brilliant puzzle, with lots of interesting logic.
Quite tough, but not nearly as bad as some of the comments here suggest.
A very smooth solve path, though I got stuck a couple times because I got positive and negative the wrong way round.
on 25. August 2023, 18:31 by lerroyy
Great puzzle!
on 8. March 2023, 00:06 by filuta
loved it! really inventive, pure pleasure to solve and inspirational also
on 15. January 2023, 09:17 by Agent
Absolutely incredible puzzle! It must have taken forever to create this. The way these clues that seem to carry so little information lead to such a complex solution path is just mesmerizing.
It took me several attempts to get started, mostly because I didn't have a good strategy to approach the puzzle. But after I found the break-in, it wasn't as hard as I thought. I don't think I've felt this proud of solving a puzzle in a very long time :)
on 14. January 2023, 22:54 by Myxo
Amazing puzzle! I think it's not as hard as other commenters make it seem, however it did take me a really long time because of a counting mistake on my side.
on 26. October 2022, 05:23 by dori_polic
By far the hardest puzzle I have ever solved, and definetly my favourite. What a remarkable 7h journey that started with blanky staring at the grid for the first few hours, then finally getting an idea and then just "aha" after "aha" moments. Just stunning. Please make a #3 :)
EDIT @dori_polic: Thanks for the wonderful comment! Your feedback really makes me happy :) I might at some point come back to this ruleset and make a #3, who knows, but somehow I got everything to work exactly as I wanted in #2, so I don't think I can make one that rivals it.
on 1. September 2022, 01:09 by KNT
Easily one of the most challenging puzzles I have ever done. It was assuredly a long puzzle, but I have seen plenty longer. However in terms of sheer complexity of individual steps (without anything bordering nearly on bifurcation), I don't think I can name many things that come close to rivaling this. The logic is wonderful and frankly bizarre all throughout. Loved it
on 1. January 2022, 07:59 by polar
Spectacular! Very challenging but so very satisfying to unpick - thank you.
on 12. December 2021, 10:25 by Jesper
@harrison: thank you very much for your kind words! And congratulations on solving the puzzle.
on 12. December 2021, 07:44 by harrison
Wow! Jesper, you continue to amaze me with your ability to come up with the cleverest rulesets that lead to the most difficult and beautiful puzzles.
on 4. December 2021, 00:49 by Jesper
@Phistomefel: I can't tell you how happy I was to see your solve of this puzzle and the wonderful comment. It has been a long 6 month wait to see if there would be 10 people able to solve it. And i do think that you have every right to be proud of the achievement of completing the solve :)
on 3. December 2021, 23:38 by Phistomefel
I am very proud to finally have solved the puzzle and to be the tenth one to give it a rating. The logic in it was impeccable and very beautiful. Also, I have the feeling that I should include the achievement of solving this puzzle into my CV. :)
on 10. September 2021, 10:56 by Vebby
Brilliant opening logic! I struggled a bit at the end because of one oversight, but finally found the solution. Chuffed! :)
EDIT @Vebby: Thanks, and congratulations on solving this puzzle, which might very well be the most difficult one that I have set! /Jesper
on 3. September 2021, 22:16 by Jesper
@Mark Sweep @JayForty @hurrdurr: thanks for the wonderful comments! It is really nice to see the solve count still going up on this (very) challenging puzzle :)
on 3. September 2021, 16:37 by Mark Sweep
This is a mindblowing puzzle. It took me multiple instances of staring at the grid before I even understood how to possibly start this puzzle. After that it was a joy to solve, remaining challenging until the end and using every bit of logic this ruleset has to offer.
on 30. July 2021, 21:28 by JayForty
Beautiful puzzle! It took me a few hours for sure but it was very enjoyable and fun to explore the ruleset. Maybe it was me getting more and more tired, but I found the puzzle harder the further into it I got. Almost every step was challenging and very satisfying to figure out. Thank you for a brilliant puzzle!
on 17. July 2021, 22:12 by hurrdurr
Absolutely amazing that you are able to create such a complex and difficult puzzle with a fairly simple ruleset. Thank you for this beauty!
on 4. July 2021, 21:50 by PixelPlucker
Incredible! This took me most of my Sunday to solve, but it was well worth the effort. Very rewarding solve path with a beautiful break-in and a long sequence of challenging deductions.
It really pushed me to study the grid carefully, be rigorous in my counting and note-taking, and use the directional loop in clever ways. Every step felt fair and elegant, and the logic was always worth finding. Thanks for this uniquely difficult and very satisfying puzzle!
EDIT @PixelPlucker: Thank you very much! It means a lot to me that you invested the time to solve this puzzle, and that you wrote such a wonderful comment!
on 3. June 2021, 00:57 by MagnusJosefsson
I test-solved this for Jesper and enjoyed it a lot. It is definitely very difficult, but once you build up a sufficient experience of the ruleset, I think it flows very smoothly (I actually struggled more with the first one). It also has some really elegant and clever logic. For me it was a very rewarding and satisfying puzzle to solve.
