How Can This Sudoku Be Real?

[@martysears]

Hey puzzle peeps, Marty here. Just finished watching, and had a big smile on my face throughout. I was even more excited than ever to see this particular puzzle featured, because I definitely consider it one of my favourite constructions. After I had come up with the idea and started testing it out, I was blown away by how much that German Whisper snake started to direct itself around the grid in a forced, unique way, with very little other input from other clues. I'll go into a bit more detail about how this came together, for anyone who's wondering... A couple of months ago, in mid October, I was going on holiday to Romania. I was standing in a long queue for security at Stansted airport, and as usually happens when I'm in that kind of boring, tedious situation with only my mind to keep me occupied, I started thinking about puzzle ideas. It was only a few weeks after Circular Reasoning had been featured, and I was still thinking about lots of potentially cool ways to use the circle counting rule. One idea that came into my mind was: what would happen if you used the circle rule along a snake that has to follow another familiar rule, like a German Whisper? In the next 15 minutes, I came to the same conclusion that Simon did during this video... that a GW counting snake must be made up of nine 9s, and interspersed with low digits. I considered a few line types, and the entropy line was also a big surprise. It would be entirely forced to be 7s, 6s, 3s, 2s and 1s! This isn't the sort of thing you can invent... it was a complete discovery, of the kind that gets you excited and makes other people in the airport queue wonder what you're smiling about. I knew this would be a very fun thing to deduce at the start of a puzzle. The third, short line is an interesting point to mention. It was originally a region sum line. If you think about that for a moment, I'm pretty sure the only valid region-sum counting snake would be 3-3-3 or 2-2. You can't have like a 5+2=7 segment, because then you need four other 5s, and only one other 2, but making 7 in each box. As soon as you introduce a high digit onto such a snake, you would need too many low digits to make the other line segments add up to the same. I realised I could make 2-2 impossible based on where I put the grey dots, and the 3-3-3 would be forced because it requires specific geometry of the boxes to make it adhere to sudoku rules. Once I got through security, I sat in the waiting lounge on my laptop, and eagerly began trying to find an arrangement, ANY arrangement, of these 3 snakes that fitted in the grid. After placing the 3-3-3 and the grey spots, and the 126 cage to stop the spot in box 9 belonging to the entropy snake, I tried growing the German Whisper snake clockwise around the grid. I couldn't believe it as its route kept on being forced and disambiguated by the next 9 needed in the next box. I realised I was onto something very cool that I loved.... and its the sort of thing that you then can't give up on, you have to keep going until you make it work. I almost missed the call to get on the plane, I was so engrossed. The flight is only 3 hours long, but during that flight, the puzzle really came together. I was listening to some Radiohead on my headphones, and one of my favourite songs by them, Everything In Its Right Place came on. It just seemed to fit what was happening on my screen so perfectly - all these components of the snakes were just fitting themselves into the right places as if by magic. I couldn't think of a more fitting title. The setting wasn't entirely straightforward of course, I had to constantly jiggle things, swap things, and decide which extra disambiguation clues to add in that wouldn't ruin the flow. I chose the Vs because they allowed me to control where some of the low digits must or mustn't be. I was sort of hoping to have even fewer clues in the final grid, maybe just two Vs, two cages, and the 6 spots. I probably could have, but I didn't want the solve to tip over into case-testing, trial and error, trying out different routes, etc, as thats never fun. So a couple of the V clues and cages were included just to keep a flow that I was happy with, and some of the most fun deductions use them. Once in Bucharest, I sent it to a few people, who tested it and gave very good feedback. But several people said that deducing the region sum snake contents was the hardest bit, because although, like me, they felt in their gut that it must be 2-2 or 3-3-3, they were struggling to find a conclusive logical proof of why, or that there weren't other options. If I was honest, I felt the same, and even though I loved the thought of the region sum snake, I was a bit unhappy with the clunkiness of that logic compared to the other two snakes, which had fairly clear proofs once you think about it a short while. I tried to think of ways to get around this problem, brainstorming other line types, but it was the genius Dorlir that suggested using the slow thermometer in place of the region sum snake. I thought this was a great shout... it also resulted in the 3-3-3 snake, so I wouldn't need to change anything else in the puzzle, but the logic for that was a lot clearer to visualise and prove, and I also liked it because it is very different logic from the other two snakes. So thanks Dorlir for letting me finish this puzzle off - it was the icing on the cake! This is my favourite CTC feature to date - not only did Simon showcase every single intended step in the way I hoped, but his reaction to some of them were priceless. He was very quick too, for the majority of it. I'll forgive him for not making the German Whisper green, haha, because mostly I'm just happy that he managed to convey some of the awe I originally felt myself in the airport, that such a thing could exist. Thanks again CTC for all you do, and all the kind words! PS: can't wait to watch Mark again on Countdown tomorrow! Am sure he'll smash it again

[@maspleben]

This was completely mental. Congratulations on this perfection Marty. Not sure I needed this on my sunday night before night time though! My brain is fried! :-D Edit: and the story of how the puzzle came to be is as interesting than the puzzle itself

[@chris5619]

I definitely consider this one of my favorite constructions as well! Not just by you, but of all the puzzles I've played!

[@davidrattner9]

Absolutely another masterpiece from you!! Cherished going inside your brain as to how you constructed this! Fascinating as always!!

[@msgeryjo]

What a treat to hear how you created the puzzle!

[@ufdigga]

Marty, that was one of the most enjoyable puzzles I've ever done. I was blown away! And I was quite tickled by your story, because I did the entire thing on a flight from Denver to Dallas. I ended up letting almost the entire plane empty out past me because I was so busy finishing it. Remarkable!

[@AdamBerkan]

Solving this puzzle is constant alternating between "There's no way there's enough information for this to uniquely solve" and "There are so many constraints there's no way this can solve"

[@martysears]

That’s a good point… some rulesets just hit that sweet spot of restrictedness. If something is toooo restricted it might make for a very brilliant miracle type puzzle, but it might be almost impossible for me to find a workable solution while setting. And if something is not very restricted then it is a lot easier for the setter to find a solution (the majority of puzzle rulesets don’t even call for any particular criteria in the finished digit arrangement, so there is no pressure or restrictedness in that sense)… but then it’s much harder for the setter to force a solve path without adding a lot of extra clues and faff. The most exciting feeling as a setter is “this is so restricted that if I DO manage to find a solution then I will need hardly any clues to direct it, it will practically fill itself in” and then it’s just a case of me grafting until I can find something. Loop Limit and The Magic Column were two other puzzles where I had this experience too; where I had to find a solution first and then work backwards a bit, adding in just a few extra clues to make a solve path that would lead to it.

[@HunterJE]

"Let's make the whispers snake blue" AGGH!

[@mikedonnan6541]

🤓🤦‍♂

[@pouletbelette]

😂

[@biaberg3448]

I didn’t notis, too exciting.

[@Jindychick]

I know!!!

[@kempisthomasa7311]

I know, I had to keep reminding myself that green wasn’t the whispers line

[@trappedxunderxice]

simon, i don’t often comment on videos, but the fact you don’t write down your deductions about how the snakes could possibly transpire and simply rely on mental fortitude is truly mesmerising. thank you

[@omribena]

forcing us to follow when the whisper line is blue and not green is just cruel

[@gi0nbecell]

Also, entropic should be orange and any thermo grey, even a slow one…

[@chris5619]

I immediately decided to make my whisper line green (and shade the ends green), the thermo gray, and I made my entropic blue, but I know blue is generally equal sums, but couldn't remember what entropic usually is. I was thinking red, but the other person said orange.

[@animeshsharma5666]

Simon be trolling all of us hard

[@janerobson2297]

Simon just wanting to make it harder for himself!

[@KaiJellyDeen]

when he said purple for the slow thermometer, i swear my eyelid jumped

[@azrobbins01]

Even after watching literally hundreds of your videos, I still have no idea how to actually begin puzzles like this. Amazing talent!

[@eyvithorgeirsson6028]

The GAS puzzles are great for people who are just starting to solve sudokus. They helped me a lot. Then you gradually increase the difficulty of the puzzles you solve and eventually you’ll become very good at it

[@windybeach2184]

I usually start with 15 minutes of brainstorming where I scribble on notepad or test a bunch of digits to see how the patterns start to form. I feel pretty clever when I find the break-in myself, then I hit play and watch Simon figure it out almost immediately with just his brain 😅

[@rahulmenon3254]

​@windybeach2184 Yeah its crazy, I spent soo long figuring it out and then I see Simon just breeze through all three snakes

[@MichaelMoore99]

Breaking into a puzzle is the hardest part, I feel. Once you get going with the first few deductions, it gets easier.

[@patrickgass787]

It's so good to see this featured! When many people (including Marty himself, I believe) rate this as one of his best, you know you're in for a real treat.

[@vjtocco]

Praise gets heaped onto puzzles on this channel quite frequently, but this puzzle truly took my breath away. It is a perfect masterpiece. Every deduction feels well earned and the title rings so true as it fills in.

[@martysears]

❤

[@fufighter100]

So I had to call in to work today due to anxiety but at 38:44, you made my day and put a huge smile on my face with a perfect Mr Bean expression. Thank you thank you whether it was intentional or not.

[@baumundallesandere]

And now you made my day with that time stamp :)

[@RichSmith77]

If I ever were to run into you at a party, I now know what my first question would be... "That time you solved Marty Sears' excellent Everything In Its Right Place puzzle, why on Earth did you choose GREEN for the entropic line and BLUE for the German Whisper line? Was it a deliberate ploy to generate KZbin comments? You mad genius."

[@chitraagarwal8259]

Marty this was just mad! The best part was that once you figured what went on each line the puzzle was actually really simple to fill in (although Simon did manage to overthink his way through that as well by thinking about the 7s before the 9s which were obviously more difficult to place!) Just stellar.. Hope you do a setter video for this

[@raynmanshorts9275]

Those last 10 minutes. Holy crap. "There's no way he can finish this!" And Simon proves what a master he is.

[@studgerbil9081]

I am utterly convinced that Simon could solve this in 20 minutes or less if he was forced to concentrate due to time contraints. This proves it. With no distractions, he whipped through the end game in record time.

[@raynmanshorts9275]

@@studgerbil9081 It really puts it into perspective the few times I manage to notice something before Simon. I may be watching the video at x2 speed, but Simon is playing Sudoku at x.1 speed. He approaches these videos very leisurely.

[@chitraagarwal8259]

I would love to see Simon do more sudokus with time constraints!

[@dwebb2805]

not since the "difference of squares" puzzle have i watched a ctc video and just been in complete awe from start to finish. every single thing about this puzzle is just insane in all of the best ways! absolutely blown away by marty's setting, and simon's solve (other than some less than optimal coloring choices) is just great. this is one of those experiences in life that i don't think i'll ever forget

[@martysears]

That is a really nice comment to read, Difference of Squares was a mindblowingly clever bit of work. Thanks :)

[@brianarsuaga5008]

I didn't attempt this myself, knowing better, but really enjoyed following along. I think this is the coolest puzzle to date on the channe. I know that's tough to say, and perhaps my memory is short, but it really is something special, weaving those rules together so that they just so neatly coalesce. Gorgeous.

[@DanielHuschert]

I’ve been following this channel for 4 years, and this puzzle - miracles, empty grids, Schrödinger cells and everything aside - is the single most mind-boggling and amazing construction I have ever witnessed.

[@jeremyblack1929]

Holy crap this is right up there with one of the best puzzles I've ever did. What a setting. Logic flowed so beautifully, each step feeling tantalyzing close every time, but still not giving up it's truth too quickly. What a great brain worm.

[@danielkelly7749]

To think someone created this and there only being one way to complete it is astounding.

[@chocolateboy300]

I finished in 147 minutes. This was one of the most insane, but enjoyable puzzles I have ever done. It is so surprising how much information is packed in this grid and have it not break. I still can't believe that the German Whisper and Entropic lines were forced. This was an incredible discovery and a brilliant execution. I think the whole puzzle was my favorite part, especially figuring out the limitation of those lines. I am still in awe of this puzzle. This has to be one of my favorites. Great Puzzle!

[@biaberg3448]

This really seemed to be unsolvable, but Simon solved it! Hard to understand how anyone could make such a puzzle and you must be sort of a genius to solve it. Congratulations to everyone who did!

[@celery6397]

Take a bow Marty! One of the best constructions I've seen in a long while. The ruleset and then the grid at first glance seems to provide so many options that it feels impossible. Top notch construction. - Celery :)

[@martysears]

Ah thanks Celery that means a lot coming from you. Big fan of your puzzles

[@onion013]

This was absolutely bonkers, in the best of ways

[@ChristyDavis77]

This is one of the most enjoyable solve with one of the most intriguing, complex rule sets I have ever seen. Absolutely enthralled by the solve path!

[@derekjc777]

This is just an amazing puzzle. The miracle sudokus look impossible, but this ruleset of diagonal travelling snakes and circle logic is truly amazing. I think this is probably my favourite puzzle from the channel. Well done Marty! Difficulty turned up to 11...

[@Stompound]

This was one of my favorite solves to watch on the channel to date. Very interesting and fun.

[@SourabhDas95]

One of the nice meta ideas with the whispers line which I didn't see mentioned, is once you figure out there are nine 9's on it, and you've found the starting and end points near the bottom of the grid, you have to get to the top of the grid for the 9 in row 1, and all the way back again, so every move has to contribute to some vertical movement to allow for skipping a line for every 9 on the way up, to leave room for collecting 9's on the way down

[@martysears]

that is a very good way of thinking about it :)

[@cathybryant5119]

Exactly. I kept asking Simon questions like - "where is the 9 in column 9?", "where is the 9 in row 1 or column 1". These thoughts definitely sped up the solve, but sadly Simon wasn't listening to me. 😂

[@21deezer]

Amazing puzzle and an amazing solve, well done Simon

[@jekoki01]

This was an amazing solve to watch! Absolutely enjoyed every minute if it! I’ve been watching and following along with your videos for a long while now, but this is the first time I just felt like I had to leave a comment!

[@martysears]

And I'm very happy you did :)

[@WarttHog]

Marty and Simon, you are BOTH absolute geniuses! As soon as I saw the ruleset I immediately said to myself, "Oh dear. Maybe I'll just sit this one out. HOLD ON! Only an hour twenty including introduction?!?!" I was shaking my head for most of the video! Absolutely masterful solve of a breathtaking puzzle! My hat is off to you both!

[@herberturururu]

This may be my favorite puzzle I've ever solved. It took me a good long time but I got it in the end. Truly incredible

[@angec9908]

Simon’s mental gymnastics at figuring out the whisper line is all 9s, and the entropy line is 6s and 7s will always amaze me. But when he forgets the rule that brought him to this conclusion of only one 1 on a line to figure out where the whisper line goes into box 4 also never ceases to amaze. I love his brain. Also the fact that he made the entropy line green and not the German whisper line had me 🤷🏻‍♀️. I guess it goes along with him making water purple and land grey 😂

[@Silvergrooves42]

This puzzle has been living rent-free in my head for the past month but I couldn't remember who made it or what the title was so this was really nice to see. Can't remember the last time I've gone "no way is this puzzle physically possible" so many times in a single puzzle. Amazing setting work and definitely one of a kind.

[@David_K_Booth]

What a remarkable puzzle! I can only applaud the imagination and skill of the setter.

[@jaega4247]

Beautiful puzzle, and also great solve by Simon as always!

[@RichHarrisThatBaldGuy]

I absolutely love watching/listen to you figure these out!

[@barefootalien]

Amazing. He actually _completed the puzzle_ without drawing all the lines. The lines that were meant to be clues. Simon, you are a marvel... your stubborn refusal to do the obvious logic of the puzzle is just incredible! :P

[@brianj959]

What’s even more amazing is that he resorted to sudoku (of all things) 😂

[@jukmifggugghposer]

This is one of the rare puzzles that I started solving in my head as Simon was reading the rules. Really wonderful ruleset. I actually managed to make progress on the entropic snake before doing much of anything with the whisper snake - it's been a day so I couldn't say exactly how, but I found out that it couldn't go high-low-mid for some reason. I believe it had something to do with column 7, and how the snake had to squeeze through the thermo snake and the cages. After that, I got a bit further with the entropic snake before giving up and moving on to the whisper snake, which turned out to be a much more useful place to look. It was really fun the way I did it though - really fascinating how the middle cage forces the 7 snake to go around in a circle.

[@_-_-Sipita-_-_]

28:35 for me. totally a banger sudoku, makes you analyze how restricted all the snakes are.

[@davidrattner9]

Great solving Simon. Love how excited you get when you come up with digits and your explanations are spot on!! HAPPY BIRTHDAY TO YOUR SISTER! Hope she had a fabulous day with chocolate cake!!

[@hanw3456]

Thank you very much David 🙏 Unfortunately I had a nasty bout of covid which is still hanging around, but will be sure to celebrate once better! I did manage some cake though 😋 😉

[@sarahnash7174]

Fabulous solve of a beautiful puzzle!!! Congrats Marty, much deserved 😁

[@chris5619]

I also started by realizing the whisper had to be nine 9s, and 8-10 smalls, which had to include 3 and 4; then realizing the entropic had to be seven 7s, six 6s, and 123 123s; and then as soon as I realized the thermo had to end in 333, I quickly realized all threes had to be equally distributed on the lines. I was a little surprised Simon didn't make the same realization, and it obviously isn't necessary, but I do feel like it helped me speed things up a few times.

[@sirgeremiah]

Yeah, once I scanned the puzzle and realized my early easy entries (the V's and such) weren't very useful yet, I went to the math of the lines. I have a whiteboard next to my desk, and I wrote the requirements (with variations I crossed off as I eliminated them). It felt very helpful, but I kept messing up - I think with basic sudoku.

[@Paul-cn3ij]

53:13 and very enjoyable. I had completed the German Whisper line bar the last 3 and 4 before even starting the Entropic line. Love the way that the last deduction was the 3 in box 9 forcing the 3 in box 4 into the GW line. Great puzzle Marty.

[@crazypantaloons]

"What am I talking about? It's not better!" This is going to be an epic solve!

[@hystrixlignum8983]

This was more exciting to watch than any thriller. Phenomenal!

[@altenaroger]

Very cool puzzle, very cool solve! Thanks Simon and Marty!

[@barefootalien]

This puzzle was fun! The way I went about it at least, was drawing the lines first, in a branching mess, and gradually eliminated branches as the lines interacted with each other and the sudoku. Fantastic puzzle!

[@pardox28]

This took me an hour and 20 minutes to solve but I'm quite proud I was able to solve this puzzle. I reasoned out what digits must comprise the entropic line first & how it had to start and end with 7s. Because that line also used 6s, I knew the German Whisper had to use 8s or 9s. Because you had to have at least 7 lower digits, it had to use 4s, which meant 9s were on the German Whispers but not 8s. Then it was all about finding where the slow thermo was. It took my slow brain awhile to realize I could skip a number before I was the 1, 3, 3, 3 path. Using the 9s I was able to find the path of the whisper. And then I figured out the path of the entropic. But the entire path felt very logical to me. I highly recommend this puzzle to included in any future CtC book. What a delight!

[@longwaytotipperary]

Wow - that’s a lot of rules! Good luck, Simon! Love the beautiful blue shirt!!

[@davidrattner9]

Simon as usual solved with aplomb and panache! The blue did stand out today!. 🙂💚💛

[@longwaytotipperary]

@@davidrattner9 💕💕💕💕

[@glebanufriev]

Always funny when Simon leaves Sudoku rules as last resort, I got pretty much everything solved after getting the slow thermometer and German whisper done, without touching too much the entropy but needed it to finish the x wings and could complete the Sudoku itself without drawing the rest, just did it to check in the end :)

[@inspiringsand123]

Rules: 05:10 Let's Get Cracking: 09:36 Simon's time: 1h9m36s Puzzle Solved: 1:19:12 What about this video's Top Tier Simarkisms?! Three In the Corner: 2x (44:41, 46:14) The Secret: 2x (03:25, 06:54) And how about this video's Simarkisms?! Snake: 111x (05:21, 05:28, 05:31, 05:55, 06:07, 06:09, 06:22, 06:28, 06:31, 06:35, 06:42, 07:04, 07:12, 07:16, 07:26, 07:29, 07:36, 07:38, 07:38, 07:41, 08:32, 08:46, 08:53, 10:20, 10:37, 10:48, 10:55, 11:02, 11:06, 11:27, 11:31, 12:20, 12:39, 12:39, 12:41, 12:50, 12:53, 13:40, 14:27, 14:29, 14:42, 14:46, 14:51, 15:00, 15:02, 15:06, 15:09, 15:24, 15:42, 15:45, 15:54, 16:14, 16:18, 16:25, 16:36, 18:59, 20:50, 20:53, 21:13, 22:20, 22:21, 22:39, 23:56, 24:05, 24:54, 38:52, 38:55, 41:19, 41:19, 42:19, 42:29, 42:48, 42:52, 43:04, 43:10, 43:10, 43:38, 43:50, 44:17, 45:57, 46:05, 46:32, 48:08, 48:12, 48:20, 48:29, 48:54, 50:41, 51:09, 51:18, 1:02:03, 1:02:48, 1:03:05, 1:03:09, 1:03:09, 1:03:43, 1:03:52, 1:04:31, 1:06:33, 1:07:21, 1:10:14, 1:10:58, 1:10:59, 1:12:55, 1:14:01, 1:14:04, 1:14:12, 1:14:15, 1:15:12, 1:16:14, 1:18:38) Ah: 27x (10:17, 12:23, 12:23, 14:34, 17:14, 22:03, 29:02, 31:00, 33:40, 40:53, 41:10, 51:31, 54:55, 1:02:59, 1:03:13, 1:03:39, 1:03:39, 1:05:51, 1:06:45, 1:10:06, 1:10:54, 1:10:54, 1:13:14, 1:14:12, 1:14:12, 1:16:05, 1:16:19) Hang On: 14x (10:17, 30:00, 39:13, 39:13, 39:13, 44:44, 53:18, 1:08:35, 1:11:27, 1:12:33, 1:12:33, 1:13:14, 1:15:53, 1:17:01) In Fact: 8x (14:02, 25:47, 25:47, 27:18, 35:43, 53:37, 53:57, 1:13:58) Clever: 7x (27:27, 27:27, 42:43, 42:47, 45:00, 45:03, 1:04:08) By Sudoku: 6x (48:59, 49:05, 53:05, 1:04:27, 1:05:32, 1:14:35) Obviously: 5x (09:06, 11:52, 17:10, 32:09, 54:15) What Does This Mean?: 5x (29:46, 41:34, 43:27, 47:41, 1:09:05) Sorry: 4x (12:33, 14:37, 49:32, 58:03) Weird: 4x (10:57, 31:45, 50:18, 50:20) Goodness: 3x (18:56, 50:18, 1:08:07) Lovely: 3x (02:43, 25:28, 1:05:14) Beautiful: 3x (41:29, 47:57, 47:57) Brilliant: 3x (02:18, 1:01:52, 1:01:59) Come on Simon: 3x (49:12, 51:58, 1:14:27) Unbelievable: 3x (01:07, 42:06, 42:09) That's Huge: 3x (25:47, 1:07:34, 1:07:34) Pencil Mark/mark: 3x (22:00, 50:12, 1:04:38) Unique: 3x (01:22, 1:07:06, 1:08:30) What on Earth: 2x (20:04, 41:47) Insane: 2x (1:19:20, 1:19:23) Ridiculous: 2x (41:29, 53:15) Surely: 2x (32:49, 41:03) Wow: 2x (1:14:04, 1:14:04) Bother: 1x (1:11:13) Nonsense: 1x (17:30) In the Spotlight: 1x (46:17) Stuck: 1x (59:01) Horrible Feeling: 1x (30:17) Astonishing: 1x (01:17) Hypothecate: 1x (40:56) Bonkers: 1x (25:39) Shouting: 1x (04:24) I've Got It!: 1x (41:10) Have a Think: 1x (59:20) Nature: 1x (55:25) Most popular number(>9), digit and colour this video: Ten, Fourteen (5 mentions) One (148 mentions) Blue (15 mentions) Antithesis Battles: Low (74) - High (14) Even (18) - Odd (1) Higher (7) - Lower (4) Row (10) - Column (4) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!

[@danielszanto2955]

Simon finding out the composition of the snakes is the greatest sudoku comedy.

[@MattCarlyle-e6q]

Fantastic, difficult, satisfying break-in. I was able to make a little more progress on the entropy line in boxes 9 and 6 (right at the choke point where Simon stopped at the beginning) and that helped disambiguate a few things and showed how the lines were going to coexist. When I saw Simon's solve, I was amazed he could complete the GW line without having learned more about the entropy line, but that's typical Simon, seeing much more that I ever could. Amazing puzzle.

[@sjm6280]

I loved this puzzle, and Simon's solve!

[@przemekmajewski1]

fantastic 55 mins solve, that was fun! I'm late to errands after that

[@MeriaDuck]

That was quite brilliant again, we will be filling lots of books with greatest hits! Wow!

[@ayakoa2096]

54:34 for me, One of the best Puzzles I have seen so far, incredible how the constraints interact with eachother.

[@titusadduxas]

1:12:26 - Astonishing puzzle with some gorgeous logic. I am so chuffed to have done it unaided! (I say unaided but of course without 18 months of watching CTC I’d have laughed in the face of this one and declared its impossibility! )

[@chrispowell1455]

Absolutely astounding - I really couldn't see how that would even get started!

[@Rubrickety]

This puzzle is breathtaking, and I'm quite proud I managed to solve it (in just under 2 hours, quite respectable for me!) These new-ish "self counting" rulesets are proving to be a wellspring of marvelous constructions.

[@awebmate]

Very satisfying puzzle to solve. Even looks like a piece of art once you are done.

[@Richard_A._Watson]

That was amazing, both in setting and in solving! :)

[@ri3545]

Simon is a radiohead fan?? I like him even more now

[@altreusplays]

Simon’s logic about the whispers line is called the fence post problem (because it’s usually a problem in the other direction): if you have 7 fence panels you need 8 fence posts, often manifesting as an off-by-one error. The converse is that if you have 8 8s (the fence posts) then you need 7 low digits between them.

[@bradmccallum1]

Interesting to see how Simon's mind works. I figured out the path of the Whisper line by thinking that with all 9's on it, then you had to have a 9 touching all 4 sides of the grid (by Sudoku). Which gave me the 9 in boxes 2 and 4 right away.

[@wanderlustwarrior]

1:11:09 for me. That was very challenging, but incredibly brilliant construction. I thoroughly enjoyed how certain numbers had to be forced onto one type of line and out of another.

[@uncgoalie]

44 minutes - at first I thought there is no way for me to solve it, but once I understood the logic of the line rules' impact on the digits, it all fell in the right place...

[@noahvale2627]

So glad you called the purple line pink, it always looks pink to me.

[@mostman]

This is an incredible construction. I can just imagine thinking about a whisper line where the numbers on the line had to repeat that number of times. But then to think, yeah, let’s do a puzzle around this and make the solver find the lines. What? Simply stunning. Edit: And I just saw Marty’s comment above. That was the genesis. What an absolute genius. Congrats Marty - what an achievement.

[@martysears]

Thanks very much Mostman! Happy you enjoyed the little backstory too, when I'm in the middle of writing those I always have the thought of 'does anyone actually care about this?' hahaha

[@mostman]

@@martysears Oh we care. Trust me, we care!

[@turbochrist]

Complete, sheer and - albeit beautiful - utter madness.

[@Robert_H.]

*Logic for the Start* German Whisper Snake: has to be 17 to 19 cells long, has 9, 4 and 3 on it, but no 5 to 8. - can't have 5 (German Whisper) - can't have 6 (needs at leat five 1) - can't hvae 7 (needs at least six of {1,2}) - can't have 8 (needs at least seven of {1,2,3}) - needs a high digit on it: 9 Entropic Snake: Snake has to be 19 cells long, has 7, 1, 2, 3 and 6 on it - can't have 9 (used for German Whispher) - can't have 8 (needs at least seven of {1,2,3}) - needs a entropic high digit on it: 7 - can't have medium digits 4 or 5 (only seven entropic high digits) - needs a medium digit on it: 6 - needs all entropic low digits in it: 1,2,3 - starts and ends with 7 Thermometer Snake: Snake can't be longer than 6 cells, doesn't have 4 or higher on it - can't have 4 or higher (no possible set of four connected cells with the same digit in Sudoku) - can only use 1,2,3 33:45 START

[@martysears]

This a spot-on perfect summation of the main logic that leads to the contents of the snake at the beginning of this puzzle. Thanks 😊

[@Erin_Solstice]

Wow, what a puzzle! I managed to get it done in 65:39. Very happy to have managed to do such a beastly puzzle. I had a small issue at the start when I for some reason assumed the slow thermo snake started with 2s (I guess because I was thinking of the numbers having to be consecutive) but that very quickly broke the 9 cage and I realized my mistaken assumption. Thankfully it wasn't too hard to correct that and then find the actual logic that figured out it was a 1 without using that bifurcation. Figuring out the thermo snake was the hardest part. It was very difficult to prove to myself what circles could or couldn't be part of it and then figure out a way that it would actually work.

[@mstmar]

im surprised. i solved this in the complete opposite direction than simon. simon did slow thermo first, then entropic, then whisper, while i did whisper first, then entropic then thermo. my first deduction was that 9 has to be on the whisper, same as simon. the next thing was to ask where the 9, which is on the whisper has to go in the bottom row. basically, every 9 needs to be 2 away from 2 other 9s or to a circle. the only place that doesn't force a 2nd 9 in a box is r9c4. it has to connect to the circle above it and to a 9 in box 7. the 9 in box 1 has to be in cols 2 and 3, which align with the 9s in box 7, so the 9 in box 4 has to be in col 1. since that 9 isn't near any circles, it has to connect to 2 other 9s, and must be in r5c1 connecting to box 1 and 7. continuing like this, i got all 9s placed and most of the whisper line placed. this made it trivial to find the end points of the entropic line, since the other circles were either whisper or had low digits on them. then placing the line was similar to what simon did, but with a lot more digits in the grid than simon had. finally when most of the grid was in, i did the thermo

[@TurquoizeGoldscraper]

Great solve, Simon. I had no idea where to start.

[@prahas777]

Another totally next level construction. Whoa!!!!!

[@jkwatcher47]

I followed along and when he gave up on the green snake I continued on and finished the green snake first and then finished the blue snake and the rest. So much fun!

[@kevinmartin7760]

A green entropic line, blue Whispers line, and a pink thermo... Simon is showing his daring colour sense again!

[@madeking4]

One beautiful piece of logic you missed is asking where the 9 can go in row one and Column one. Because they have to reach two 9s in different boxes, they can only ever be in the middle. Then you have to draw a straight line between them as it's the only way to take a 9 in box 1 and leave. So you can place those 9s without having any other digit in the grid.

[@martysears]

Ah that’s a nice observation, I hadn’t really considered it like that before. I started by asking where 9 went in the bottom row and kind of worked clockwise around the grid, from that end of the snake to the other end. But I’m sure there’s lots of different orders you can do it in, but hopefully all are fun 😊

[@LucieBoleDuChomont]

Just under two hours for me, it was very cool! Very challenging too, and I used the "pen" tool quite a lot to draw hypothetic snakes.

[@mery1973able]

Absolutely briliant puzzle!!!!

[@XandrianBro]

43:20 "What does that mean?" It means 3 in the corner🎉

[@samueldeandrade8535]

26:29 man, I love watching Simon being smart. Hehehe. I would love to interact with him at a party.

[@FrancisFjordCupola]

Once the nature of the whisper line is deduced (1234's and 9's) is deduced... the big question to me became where does the nine fit on the extreme/border rows and columns. Because the whisper line features 10 low digits and only 9 highs, both the endpoints must be low. Each box must have a single high number. But also each box can only have a maximum of two low digits. Then again, made a few subtle errors such as placing the 3 in the second column in box four, whereas it should have been in the first. Simply misplaced the routing of the whisper. That caused a lot of issues figuring out the entropy line. Still insane puzzle. One really has to know how to figure out how the lines work. With the snake crossing over I managed to plant a 122333 thermo, but both two's blocked off other lines. Took a while to realize that 1333 was just as valid. Totally only looked at the entropy line after the other two's.

[@lunardancer6047]

The logic works perfectly well without even considering the "snakes can't enter cages" rule as I forgot that part of it but still managed to solve the puzzle.

[@martysears]

interesting... how did you deduce that the spot in the bottom right corner is on the German Whisper snake rather than the Entropy snake? For me that uses the 'don't go in a cage' logic, because the entropy snake would need a 6, which is in the cage. If it could go in the cage then it could get the 6

[@lunardancer6047]

@@martysears I figured the bottom left cell couldn't have been on the Whisper snake as if it were, it would have taken the 9 in box 7. Which means the other Whisper end in Box 8 had to take a 9 from it's own box. At that point, wherever the 9 is in Box 9, it can't connect to two other 9s, so it gets stranded (as it can't use the 1 in the thermometer snake as a bridge). Therefore the 9 in box 9 must only connect to one other 9 because that is actually the last 9 on the snake, with the cell in the bottom right being it's end. I hope that makes sense, sometimes putting these thoughts to words is difficult (it makes sense in my head at least, LOL).

[@kevinerose]

Wow I was so stuck until I found the thermo. Nice puzzle!

[@Hossafy]

I think this puzzle is over my limit. I love a good ruleset, but my head was spinning before we even got off the ground.

[@jetzeschaafsma1211]

Once the Threes are in place for the Slow Thermo, the biggest question is how the German Whispers line can visit all Boxes and Edges in 19 squares max, which leaves almost no wiggle room. After you got the start and end Sevens, you don't even need the Entropic Line aside from some last-minute disambiguation.

[@leestoddart7014]

Brilliant puzzle and excellent solving. But Why oh why oh why did you not use green for the German Whisper line?

[@rahulmenon3254]

An absolutely brilliant puzzle, just a joy to solve, took a whole 1:17:15 to solve but really worth it. Can't even imagine the genius that goes into setting this.

[@johnallegood4469]

I ended up mostly solving (and pencilmarking) the 7s first, which made the 9s a bit easier took me 52 minutes overall but it was very enjoyable

[@andrewgrant6516]

Outstanding in his field.

[@007thn]

Brilliant piece of puzzle!

[@ChrisWEarly]

I'm ten minutes into my solve and had to pull up Excel to figure out ho to do the German whisper. What a neat logic hurdle.

[@TaismoFanBoy]

I think this was the hardest sudoku I've ever solved on my own. My time was 34:38. However, I actually started by looking at every pattern that the 9s could possibly fulfill. As far as I could tell, only one possible selection of 9s could ever fulfill the puzzle properly from the very beginning. In order to fill every row/column/box with a 9 and have them all be connected, you must have 4 nines on edges. However, to each all 4 edges, you either make a mad sprint (which would leave all 4 9s as in the edge centers), or you have two loose ends and two 9s on the edge centers (and obviously you can't have two 9s in a single column/row). This means boxes 2/4/6/8 must have two 9s exactly in the edge center connected by a 9 in the corner box between them. This also extends into a middle reach into the two other corner boxes, which then leads to two possibilities (asymmetrical) total. However, a 9 could never be on the V in box 8. Therefore, the straight diagonal of 9s was either boxes 4/1/2 or 2/3/6. Due to asymmetry meaning each possibility has two possibilities, that means there are only 4 total possible selections for the exact placements of all 9 9s. However, to go even further, two are easily removed by a 9 landing on a V, and the last one can be removed by the endpoint 9s not landing next to snake dots. This leaves only one possibility, and I could place every single 9 into the grid right from the start! It took a bit of visualization to rotate the 9s and/or flip the 9s across the symmetry to see where they'd end up, but I don't think this counted as bifurcation (or many-furcation), since I was able to visualize it pretty quickly with a few logical steps. I don't think it was intentional, but it made the rest of the puzzle far easier for me to solve, so I hope I didn't make a mistake and coincidentally get lucky with my 9s placement. If anyone sees a problem with my 9s logic, let me know that I just got lucky xP

[@martysears]

Thanks for this, that was very interesting :) It certainly wasn't intentional, but it wouldn't surprise me too much if you're right. The whole thing is very constrained, not by design but just by the nature of the ruleset. I can't imagine there are many ways to link up nine 9s, alternating with low digits between them, even if the grid was completely blank apart from the starting dots.

[@daleomiller]

That was an incredible puzzle and an equally incredible solve.

[@fredgoodyer4907]

44:54 Nooo, Simon, yes you are!! This one stung 😢

[@michaelmatter1222]

What is more impressive, the setting of the puzzle or the completely mental (i.e. no taking of notes) solve? 🤔

[@barefootalien]

58:59 "So umm... I'm a bit stuck. What should I do, d'you think?" Hmm... well, I might try something like drawing lines on the line-drawing puzzle, Simon. :P You've gone to _great_ lengths to avoid doing that, trying shading at first, drawing weird vertical lines to 'shade in' the regions through which the entropic line could pass, rather than just drawing the potential routes directly...

[@AleksandrYgA]

42:41 for me. Rules seem crazy when you read them but the restrictions are actually quite strong so you can find out what to do pretty fast

[@rhoadeshouse]

Very interested in this video because Simon gave himself a time limit. according to the videos length i assume, i wont be able to solve it o i will have to watch simons solve, who will eighter have succesfully done it, or it will be the first not cleared puzzle on the channel, very interested as i said.

[@barefootalien]

Interesting that Simon still hasn't eliminated 69 from the middle killer cage at 47 minutes. That was one of the first deductions I made! And it was instrumental in shaping the lines, since it meant there couldn't be a 7 in the middle box on the entropic snake, sending it 'round the outside.

[@zogannstorm6044]

Are we in some kind of parallel universe where German Whisper lines are BLUE?