Suspended Animation
(Published on 18. June 2022, 01:42 by Kafkapharnaum)
So this puzzle is dedicated to Sktx, and makes use of his Still Life ruleset, which is itself based on John Conway’s Game of Life parameters, and mixes it all with my own Doppelganger ruleset (plus normal sudoku). So buckle up, as this makes for a lot of rules
If any (let alone both) of these rulesets are new to you, I very much recommend trying the following 6x6 warmup puzzles (with both pages containing examples):
Sktx’s 6x6 Still Life puzzle
My own 6x6 Doppelganger puzzle
RULES
STILL LIFE
Shade some cells green ("alive cells") such that the – up to – eight cells neighboring each green cell contain exactly 2 or 3 other green cells and the neighbors of each 'unshaded' – or grey – cell ("dead cells") do not contain exactly 3 green cells
- A CIRCLED cell's digit indicates the number of cells that are in the SAME state as its own in its neighborhood, INCLUDING its own cell
- A SQUARED cell's digit indicates the number of cells that are in a DIFFERENT state from its own in its neighborhood (therefore not including its own cell)
DOPPELGANGER
– Every row, column, and box contains the digit 0 always, as well as eight out of the nine digits from 1 to 9 (ie, it's missing one digit that is not 0)
– No two row, no two column, and no two box may be missing the same digit
– For each 0 in the grid, the digits missing in its row, its column, and its box must be three different digits
*** Also, note that a zero always acts as itself (ie, the lowest possible value), regardless of what digits it's replacing in its box, row and column
SOLVING LINKS (no solution check)
Solve on Penpa (w/tracking cells)
Solve on Penpa (main grid only)
Solve on the CTC app (w/tracking cells)
Solve on the CTC app (main grid only)
Solution code: The digits in the ALIVE cells of columns 3, 6 and 9, in order, each from top to bottom (15 digits total)
Comments
on 17. January 2025, 17:33 by gfoot
Such a tough one! I do not have a good instinct for the Still Life ruleset, so had to experiment quite a bit along the way to figure out the constraints, made a lot of mistakes, and restarted several times. It was nice to then be able to apply some of the knowledge and progress in a more logical fashion! There were some really tough points where I did have to look ahead very deeply to eliminate possibilities, and when I get time I think I'll go back and resolve and try to find simpler deductions to get to the same results, which I'm sure are there somewhere!
I also made the mistake of deleting all the colouring when I'd filled in all the clue cells with digits, so that I could focus on the sudoku/doppelganger that remained - but then of course had to recolour it from scratch in order to get the solution code, oops!
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Congrats! I'm always impressed by everybody who solve this one as their first Still Life puzzle, as like you found out, it's a ruleset with quite the learning curve, that unfortunately (or so I think) leads some to think it's all about trial and error, when it actually has loads of inherent 'always true' properties for certain digits in circles, in squares, and along an edge or not, plus combos, equivalences (totalling the up to 9 cells of a given neighborhood), etc, such that, again, like you appear to have found out, allows for quick and sound progess! Huge thanks for that feedback, and again for the continued streak of solves and comments on my puzzles! :D
on 2. January 2025, 10:21 by bodemeister
Brutally hard for me. I feel I'm not very good at the still life ruleset. But I made it! Not sure how it's possible to set such a work like this. A masterpiece for sure! Now it's one vote closer to getting a red rating. xD
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Welcome back (which kind of applies to me as well haha)! Many thanks for the support on this one, and congrats on beating this beast -- to this day, I think this is still my hardest puzzle, and as you might suspect, this was first and foremost a setting challenge, that ended up not quite allowing the linear path I had in mind, making it even harder to solve, but I think it gave its solvers quite a feeling of satisfaction. Glad you enjoyed too!
And I see you posted a new puzzle, but I still want to come back to Scattered Thrunderstorms first. I see wullemuus solved it, so this is a good sign! :D
on 29. August 2023, 16:17 by wullemuus
As with every puzzle of yours the biggest challenge is to keep on going! Yesterday I was so proud of having found a solution but it was not the right one because of box1 :((. But with this little change everything was so much easier and I enjoyed the pathway very much. Gladly I found the little help as well (kept me from stopping after the first box :D). The zeros helped a lot. But the real difficulty was the still life construction.
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I saw you had solved Sktx's 6x6 (notifications for solves on favorited puzzles), and I had a feeling you were working on this one now -- congratulations on pulling through! Even with 'Leviathan' that I posted recently, all well considered, this one here might still be my hardest puzzle, and yes, that darn box 1 is certainly part of it haha
I even went into a panic when, after putting the final touch, I thought it could have two solutions, but thank goodness no, I had actually thought of that early on to prevent it, but the setting process had taken me so long and so much effort that I had forgotten it XD
As always, notifications that any of these challenge puzzles of mine have gotten a solve absolutely instantly make my day, thank you so much! :D
on 28. June 2022, 21:43 by polar
Thank you very much for drawing my attention to both your Doppelganger puzzles and Sktx's Still Life ones - both are really great original rulesets. That said, I hoped going through that wonderful back catalogue might prepare me to attempt this one, but wow it was tough as nails and utterly relentless in difficulty.
The ending in particular was brutal for me. I probably veered a little further into bifurcation territory than I would normally like, but there was no way I wasn't completing this puzzle by that point haha. Thanks :)
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Thank you so very very much for all the solves and the kind words polar! Yes, the end part has at least two rather brutal deductions, and one of them even like three times as hard as the other, but it can still be spotted by combining two "immediate" (forced) deductions, and this is where the Pënpa tracking strips and boxes are REALLY useful. If you did it all on the CTC app only, then I think we just might have to preserve your brain for future generations! XD
In any case, I gotta say, it was just beyond belief to see how quickly you went through pretty much the absolute hardest puzzles we can come up with, and with rulesets you didn't even know just days before... We're not worthy! :D
on 20. June 2022, 19:24 by Sktx
Probably one of the hardest puzzles I've ever solved, but that was so worth it ! Thanks for using my ruleset, you managed to outclass my own Still Life puzzles in difficulty, while adding that crazy Doppelganger variant into the mix (I had a hard time dealing with it during the solve, but ptogressively got the hang of the logical implications, and it's a really clever and interesting ruleset). I owe you a puzzle !
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Ha, you were really close then -- congrats! :D It's fitting that the creator of the Still Life ruleset would be the one to knock that 0 off the 'Solved' column, but that just makes that solve all the more special to me; I'm super grateful, and happy that you feel it was time well spent :-)
Now my challenge is to make an easy one, and I should have something for you to test soon!
on 18. June 2022, 13:52 by Sktx
Wow, thanks for this Kafka ! I'm gonna try it as soon as I have some free time ahead ! Seems monstruous...
Just pointing out : the rule section on your CtC link just mentions normal sudoku rules !
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Oh thank you! That was quite the unfortunate error to happen with such a puzzle haha... This is fixed now - and my pleasure for the shoutout :D
on 18. June 2022, 08:52 by PrimeWeasel
I'm still at the filuta puzzle, but I've also done Sktx's Still Life puzzles, I'm entering a dark twilight zone the couple of days I think.
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Oh man, good luck!
Daunting as it may seem, my puzzle still has nothing on filuta's, you're gonna cruch this. Judging from the time frame of your comments, you solved Sktx's first Still Life on the day of its posting, which is just mindblowing to me :O
