RAT RUN 39: Together Apart
(Published on 27. May 2026, 01:46 by marty_sears)
Rules:
Normal sudoku rules apply.
AIM OF EXPERIMENT: Finkz and Phinx must both reach different cupcakes by finding a path through the maze. The paths must not visit any cell more than once, share cells, cross themselves or each other, or pass through any thick maze walls.
As well as moving orthogonally, they may move diagonally if there's a 2x2 space in which to do so, but may never pass diagonally through a round wall-spot on the corner of a cell.
FOG: Much of the grid is obscured by fog. Entering correct digits may clear fog somewhere in the grid. No guessing is necessary.
BLACKCURRANTS: If a blackcurrant sits between two digits, one is double the other.
GRAPES: If a grape sits between two digits, they have a difference of at least 5.
STARFRUIT: If a starfruit sits between two digits, they always have the same sum, to be determined.
BUTTONS: Every circular coloured button must be visited. The digit on a button indicates the number of cells that the rat moves after that button to arrive in a different 3x3 box. (Eg: if the rat moves immediately from the button into a new 3x3 box, the button would contain a 1.)
TEST CONSTRAINT: A digit on a path may not be consecutive with the digit visited immediately before it.
Solution code: Digits underneath the grid, from left to right
Comments
yesterday, 14:41 by woody
After so many (great) variations in the comcept, I am glad to have had one more puzzle that really feels like a maze.
Thank you so much for the quality of the series! I'm really looking forward to the big one!
on 28. May 2026, 16:51 by valeryolympia
One of my favorites, thank you once again for a beautiful puzzle Marty, and LOVED the ending!
on 28. May 2026, 16:12 by l_ugray
What a masterpiece of a series you’ve created here. A massive thank you for the gift you’ve given this community of solvers.
on 28. May 2026, 14:01 by claire93
Another fabulous instalment in the series! I got really immersed in solving this one, and totally missed the linear pattern on the pink buttons until the final fog reveal, so I was chuckling to myself about your 'surprise' for the puzzle - and then BAM! that ending!! I'm equal parts excited and sad for the final puzzle to follow - I'm relatively new to the world of variant sudoku and these rat runs were my introduction to them, so they have a dear place in my heart :) Thanks Marty!
on 28. May 2026, 11:56 by AshBrown
Goosebumps. Wow
on 28. May 2026, 02:00 by Nylimb
If anyone is struggling with this as I was, make sure you're using the up-to-date version with the "little tweak to box 6". The older version has multiple solutions.
With the tweak, it's a great puzzle! Thanks.
on 28. May 2026, 00:11 by VolpeRosso
Absolutely amazing as always. As we approach the end, it is bittersweet. Sad that the greatest sudoku series of all time is almost at an end, but excited for whatever marvels Marty conjures up next.
Approaching the end also makes me wonder... Marty - at what point in this process did the full story start shaping out for you? My guess is sometime during season 1 you started getting mad ideas, and they became fully formed during season 2? Thank you sooo much for all the mental stimulation and joy! <3
Marty: <3 funny you should ask this, as I have just been writing about that in my comment under Simon's solve video. You are pretty much exactly spot-on. At the very start I didn't have too much idea about the story except that I wanted it to be mysterious and sciencey and set in the 70s. By the time I reached episode 6 it all started coming together in my head, and since then it has been like doing a big jigsaw, with some of the bigger plot-points known from early on, and filling in everything else as I went along, with the full picture gradually becoming clearer and clearer. I've never done anything like it
on 27. May 2026, 23:40 by AshBrown
Goosebumps. Wow
on 27. May 2026, 22:36 by Klausku
This one took me almost 3 hours. Some very tricky things to spot towards the end. But I enjoyed every minute of it. Thanks Marty.
on 27. May 2026, 21:54 by Exigus
Fantastic puzzle. The story is so well done as well. Thanks!
on 27. May 2026, 21:38 by dzamie
What a nice continuation to the story :)
It's kinda neat when I'm actually able to look at the finished puzzle and know which rat is which, sort of.
Very, very clever puzzle! Featuring very, very clever rodent life :D
Edit: also, every time I see a rat right next to the cupcake, I can't help but think, "what if Finkz's path wound up being like 3 cells long?" It's so, so tempting to work with the assumption that that *can't* happen - to the point where I feel like that would be really funny if one of these winds up doing that. "Yeah, Finkz just really didn't feel like running all that much, especially when there's a cupcake right next to her."
on 27. May 2026, 19:08 by blackjackfitz
Huzzah!
on 27. May 2026, 18:02 by Lykrast
Fog with two of the lesbian rats was a lot more refreshing than I expected. And yay for starfruits again. I got stuck a few times (mostly near the end) but overall was a nice. Can't wait for the finale (?) in 2 weeks.
Unrelated I was always curious how did you make that kind of stylized picture (like several rat illustrations are similar), like what filter(s) are you stacking to get that paint-like colorful effect?
on 27. May 2026, 17:22 by BG03
Is there a way to refresh one's memory on the story so far before the finale? I've tried to go through all the previous puzzles but some of my solves got lost on sudokupad!
Marty: This should help :)
https://www.youtube.com/watch?v=kCF9uLrsEus&list=PLK-l8O0YikOmTo_9JS-8mhPe0ikw4IDms&index=6
(This was done a few weeks ago so is just missing the most recent episodes.)
on 27. May 2026, 16:58 by Christounet
Pure ART RUN. Period.
on 27. May 2026, 16:21 by etoler
Marty, please stop cutting onions in my kitchen every Wednesday.
on 27. May 2026, 15:24 by mscha
Oh wow... I did _not_ see that coming! But it's a beautiful resolution that makes perfect sense. Looking forward to the finale (but not to the weeks thereafter).
Edit: Oh, I see... 6 days extra looking forward. ;-)
Very nice puzzle! A relatively easy start before it got a bit trickier. I got stuck about halfway for a long time, but that was just me missing something obvious. I gave it 4 stars for difficulty.
on 27. May 2026, 15:20 by Nairurian
That was a lovely puzzle but it definitely felt like the difficulty ramped up quite a lot in the last quarter-ish (like it went from a 3* beginning to a 5* end).
on 27. May 2026, 15:18 by GeorgeTheToad2
Marty, you have amazed us all for over a year and this puzzle is exceptional. The fog helped me by focusing me in the right direction. So pleased to finish in just over an hour, so everyone should give this a go, they will not regret it. The big one is on the same date a year on from the first - happy anniversary?
on 27. May 2026, 15:03 by Franjo
I was sure the solution code here would be - well, something special. Anyway, I enjoyed the walk(s) through the maze so much. As usual. But I’m afraid the wonderful journey will come to an end soon. Thank you so much for taking us with you.
on 27. May 2026, 11:22 by DaniK
Wonderful! (as always) Really pumped for the finale!
on 27. May 2026, 10:47 by jinkela114514
Hope that the 000RUN puzzle is also a RAT RUN.
on 27. May 2026, 07:22 by EFlatMinor
excellent work snagging the 000RAT puzzle id :)
on 27. May 2026, 06:43 by marty_sears
Made a little tweak to box 6 to address a few people's comments
on 27. May 2026, 05:11 by tryote
Awwwwww :’(
on 27. May 2026, 04:22 by jinkela114514
Why is the next episode scheduled on Jun 9 (Tue) instead of Jun 3 or Jun 10 (Wed)?
Marty: it is a year after Experiment 1, so felt appropriate :)
on 27. May 2026, 03:18 by Angara
Goosebumps! Thank you)
on 27. May 2026, 02:04 by Calvinball
The perfect puzzle ID does exist :D
on 27. May 2026, 01:50 by ViKingPrime
An immensely satisfying puzzle to solve, for so very many reasons.
