"One Of The Best Puzzles I Ever Solved": WARNING: VERY Hard!

[@davidenas]

Purple water? Grey islands? Relevant comment from Mark on a video a while ago: "I'm not going to make the water cells orange, I'm not Simon."

[@Vanziethel]

That sounds hilarious, do you remember the video? I remember the time (or at least one of the times) Simon coloured the water orange, but not that Mark comment.

[@dontmindme2844]

All I know is I wouldn't want to drink the water from Simon's tap!

[@DekarNL]

That was some emotion inducing colouring by simon to be fair😂

[@77kaczka77]

Les Rivières pourpres (2000) after Purple Rain (1984).

[@davidenas]

@@Vanziethel The video title is "Become a Harbor Master with Sudoku Skills!"

[@hom-sha-bom]

Purple and grey are the most unhinged color choices for water and land.

[@brobzoid]

"grey is the right colour for an island, not green" an extremely english statement 😅

[@sonalita_]

"And did those feet in ancient time Walk upon England's mountains GREEN?" Green is indeed the correct colour Simon!!!!

[@stevesebzda570]

😂 He's not so bad with the grey actually. Every island popping up thru the sea, is firstly bedrock (including the volcanic islands). "Bedrock" I'm tellin' ya. Now to deal with the purple or magenta sea all around. Lighter than that blue, actually. Probably better. Funny though 😂

[@benspringer6880]

Simon will Simon.

[@puritan7473]

I just took an epic 2 1/2 hour journey on a ship. I thought I was promised a relaxing cruise visiting some islands but instead I was in constant awe of the mad genius captain that managed to navigate the toxic waterways using a nearly useless map with most of the information missing. Instead of visiting the islands, he crashed into the rocks 21 times, hitting every possible island and blaming the map each time but at least he only hit each one once!

[@andy-kg5fb]

Underrated comment

[@stevesebzda570]

Puritan, and your name is "puritan" like the "pilgrims" who landed at Plymouth rock. Cool

[@Vivisions]

I’m sitting here under a gray palm tree on my little gray island, enjoying the wonderful view of the azure-pink sea and looking forward to a new episode of Cracking the Cryptic.

[@benterra4029]

29:47 "But Simon!" I scream, tears streaming down my face "All water cells have to be originally connected!"

[@drlabos]

As an update to the anniversary shoutout, Kelly has agreed to marry me. ❤ Tobi and Kiki are very pleased. Thank you Simon and Mark for highlighting these major milestones in all our lives. Your little sudoku channel means so much to so many.

[@kamalidimock8726]

Congrats!!

[@wooferzfg]

congratulations!!

[@Killrrhubarb]

Congrats!

[@alicehutchings1755]

Congratulations 🎉

[@Anne_Mahoney]

All congratulations and best wishes!

[@neilkightley3451]

21:48 Simon: "Grey is the right colour for an island, not green". Proof that Simon is not from planet Earth!

[@Hetpust]

love that 💯💯💯

[@martinbull-gundersen8878]

Proves he's not Irish at the very least 😀

[@WimmekeVL]

kzbin.info/www/bejne/kJ2xmWaijd-arKcsi=i4Di0mm6Xy1Ut006&t=33

[@rishinz]

Grey Britain.

[@RealNovgorod]

Britain recently left the Earth Alliance, so that's correct.

[@wooferzfg]

thank you for solving this one - a wonderful belated birthday present! also lovely to see a non-sudoku pencil puzzle on the channel. it would be cool to see more pencil puzzles (ideally far easier than this one!), even if the audience is initially a bit smaller :)

[@johncox7169]

Happy Birthday! :D

[@davidrattner9]

Just loss for words!! Phenomenal from you!!!

[@ttto_ok]

thank you for the ww rando tools :) wild but great to see you also on this channel

[@McMedicful]

Very cool puzzle! Thank you!

[@njihnjihnjih]

Really enjoyed the puzzle \FrankerZ/

[@maximilianosalvador9559]

In what universe is gray the right colour for an island over green?! 😂😂 and purple for water? This is a madman

Clearly a madman. Purple water and grey land...

[@sonalita_]

@ He's obviously played "No Man's Sky" where it is indeed possible to find planets with purple water and grey land!

[@inplfw]

He explains it very clearly in no uncertain terms at 21:28

[@Hetpust]

@@inplfw naaah..... nah!

[@maxt7449]

Came to the comments after 20 minutes to find this comment haha! Very entertaining this is Simon's opinion 😅

[@abcde_5949]

29:00 Simon is going for this huge deduction why this can't work, while missing the first line of the rules: Water cells must be orthogonally connected. :D

[@toms7114]

This is only true if the loop must be an orthogonal loop and can not transit diagonally, which is not prohibited by the rules. The puzzle breaks if the loop is allowed diagonal traversal though, and as such the rules should be updated for clarity.

[@crwall05]

@@toms7114 The rule says "All water cells must be orthogonally connected". So what Simon was trying (9 as an island) would not work at all since it forces the 1 water cell to be isolated and keeps it from connecting to any other water orthogonally (regardless of whether the loop can move diagonally or not, which as you mention is not specified.)

[@blahfasel2000]

@@crwall05 Yes, but without the "loop only moves orthogonally" restriction the loop could go diagonally from R8C9 to R7C10 (the "1" clue), which means R8C10 wouldn't have to be island and could serve as a way out for the water.

[@359Aides]

@@toms7114 while this is true, I'm pretty sure Simon went in with the assumption that the loop was orthogonal (at least in that line of deduction) and probably it was an oversight on the rules. With that in mind it was really a convoluted way of proving it when he could have seen the single isolated water cell he's drawn up in his coloring.

[@acantilado]

@@toms7114not sure what you are talking about. In Simon’s deduction around 29:00 he is ignoring the fact that there is an isolated water cell with no possible orthogonal connection. It has nothing to do with the loop

[@suspicious_door]

I think I’ve decided that solving this is a great way of avoiding my final exams coming up, wish me luck

[@longwaytotipperary]

Good luck!🍀

[@srwapo]

Good luck!

[@adipy8912]

When I saw your name, I didn't recognize the profile picture, so I went to Defender1031's video about Emoletional Trollercoaster to see if it were the same person and saw that you've changed the picture. It's so cool to see yet another Super Mario Maker 2 creator appearing in CTC's comment section.

[@enchanter1520]

Simon always makes jokes about don't talking to him in parties because of what he finds interesting. In that case, I shouldn't even be invited to parties, since I'm sitting here and watching a man solve a puzzle for 3 hours because I find it interesting.

[@alienrenders]

Just under 2h for me. This puzzle is a masterclass in game design implementation. The center section teaches you a bunch of simple and basic techniques on how the puzzle works. Water streams needing a clue before it can go on land. The implications of no 2x2 water blocks. How all cells with digits around an island must be water. And then you get stuck and you have to think about the overall path of the loop in each section. The puzzle just builds on each technique as you make progress. It's really incredible how it was able to accomplish this.

[@dty999]

21:42 "Blue and green. No, that doesn't feel right to me." Madness. Utter madness. In all seriousness, they have much better contrast than purple and grey for us colourblindies. Also... islands are green, and water is blue. smh

[@phueal]

Out of curiosity how would yellow and blue be? It did occur to me that this could be a desert island…

[@dty999]

@@phueal They would be fine too. The yellow and the light green are practically impossible to tell apart. This is for me, of course. Others will differ. But my colour blindness is the most common type.

[@Tof0986]

@@phueal Exactly my choice ^^

[@sacredsock8031]

Anyone remember the days when Simon used to apologize for a long vid when he was hitting the 45minute mark?

[@Hetpust]

time just flown by...nah

[@gredangeo]

We're lucky to see videos shorter than that now.

[@馬善萄]

I do dare have a go with this one, and I'm glad that I managed to solve it in 138:42 ! But every single second spending on this is worthy and I can see that every clue is carefully put together and formed a masterpiece! And the most lovely clue imo is the "?" clue in the middle of the top row, which is amazing!

[@tempota7792]

Yep, that lonesome ¿sland standing sentinel in that canal lock was also what allowed me to crack this thing wide open as well. But seeing that the 2 loose ends extend out of the core in opposite directions, it became obvious that we needed at least 1 loop back somewhere, and the only way we can double-weave something is to have at least ONE lonely island inside the canal lock! That honestly put the lynchpin in place.

[@RoderickEtheria]

Green is a perfectly reasonable color for an island. If you look at the globe, it is not appearing as purple touching gray, but as blue touching green.

[@Hetpust]

no it is gray....definitely grey... listen to Simon, he knows.... and purple. for now on.... 😂

[@michaellautermilch9185]

Simon could sell his own globes.

[@Andrewcompton22]

unless you're color blind. then your point lands a bit flat. Simon is very color blind friendly

[@RoderickEtheria]

@Andrewcompton22 So a dark green and a light blue, or a light green and a dark blue would still be possible. Even colorblind people can see the difference between lighter and darker.

[@davidrattner9]

Wow...jaw dropping when saw the length. Lets settle in for popcorn and movie night!! Cant wait. 😁

[@MrWaffles1030]

The fact that THAT square of all squares was the final one to be colored is a thing of true beauty. A perfect way for a loop puzzle to go full circle.

[@blackjackfitz]

What madness is this? Oh I love the long ones, better settle in for this one!

[@glum_hippo]

Stonking! Love the long puzzles with unorthodox rule sets. Never be shy to post more of these

[@Gonzalo_Garcia_]

2h45mins LMAO. And here I was, thinking 'I'll solve today's puzzle quickly and go to bed early'. Yeah I don't think so.

[@Cpchurch87]

Knowing some of your exceptional times, I was half expecting to see you’d done this in about 17 minutes 😂 what a tough puzzle. This is a grab some popcorn and watch kind of video

[@hubertnnn]

I decided to use this video as my go to sleep video (I fell asleep easier when watching something), but its so interesting that it just kept me awake.

[@mikew6644]

Exaaaaaactly my thought

[@Wampoe]

What an extraordinary puzzle! 2h20m of absolute joy to solve this. Without any help of Simon. Thank you for showcasing these to us and a deep bow to the makers!

[@futurefox128]

Of course there is no solution. You didn't even find a single digit Simon. :P

[@crashtextdummie]

It's neat how this puzzle evokes a feeling of going on a journey or an adventure whenever the loop leaves an island to venture into an unmapped strip of water.

[@emilywilliams3237]

I was intrigued by the shape of the grid, then saw the video length - and even though I don't have time to watch the whole video today, I definitely tuned in for the birthdays and other greetings. I almost never know a soul you're wishing a happy birthday to, but I am always so glad to hear them. I may (or may not) finish watching this video ... in the next day or two!

[@davidrattner9]

Able to finish the video today. Hope you are to. Simon's bdays and announcements always special for me.

[@enfysz1695]

honestly, ive never really known puzzles like these exist until very recently and i have fallen in love! these videos have really taught me a lot. thank you cracking the cryptic!

[@celestia7411]

Thank you for the birthday shoutout! And a puzzle from my favorite pair of constructors is a nice treat. Though devastated that Simon forgot about me after my puzzle that he featured on the channel in March 2023 !

[@stevesebzda570]

Don't feel bad. My bday is this week, and I've been here a long time, and I've never asked for a shout out. Happy Birthday.

[@originalelijah9541]

Thank you so much for solving. One of the most enjoyable (if not the most enjoyable) solves I’ve watched on the channel!

[@JohnDBlue]

I think the rules should specify that the loop moves orthogonally between cells - although the example puzzle does seemingly clarify that is the case

[@vertaz47]

I eventually solved this over the course of several days and found it surprisingly approachable. Extremely satisfying for all these small deductions to build on each other to finally complete the whole thing.

[@tempota7792]

Same here. 41 hours myself.

[@trancemission5799]

Blue and Green felt right to me - I will go and sit in the corner. and ask mysef what I was thinking.....

[@kamalidimock8726]

Lol!!!!!!!!

[@NinjarioPicmin]

that's trancemission5799 in the corner, losing their religion

[@kpopthinker3268]

simons complete dismissal of the idea too... like of course, simon, of course that doesnt make any sense...

[@RichSmith77]

Just Google "Earth Maps" and I'm sure you will be inundated with pink and grey maps...oh, hang on...perhaps if just Google "island maps" and ... no, wait, that's not it. One second...

[@arlothe_ariel]

blue and green would be great, but even if Simon didn't like that, there still was the option of blue and orange!

[@Mithical9]

Usually I'm happy to just watch the omega videos but the high rating enticed me to give it a try. It was a very involved 4 hour endeavor but I did it! The realization of the four 2x2 regions on the perimeter is a big breakthrough moment but it still fights you every step of the way. And then the opening ambiguity being the last thing to resolve is just perfect.

[@Gonzalo_Garcia_]

Around 2 hours for me. What a brutal puzzle, I can't believe I managed to solve it. I love how you need some different type of logic to break into each corner of the puzzle. Fantastic one!!

[@SirJefferE]

45:46 "how are we ever going to know whether that's an island?" If you're Simon, you're going to spend the next two hours solving the puzzle before you can figure it out. If you're a dirty cheater like I am you'll go "If this puzzle has a unique answer, you have to be able to disambiguate that cell. The only possible way to disambiguate that cell is if the island to the left has a numbered size. The only number it can reach is 13, so that island definitely connects to 13, which is also an island." I know puzzle creators don't usually intend for uniqueness to be part of the solution, but I just have too much fun using it whenever I can.

[@stevesebzda570]

Yes, that "?" clue is not going to determine that cell, so it has to turn. That cell could never be determined by an unnumbered clue. I think that was used nicely.

[@berryl_04]

I am so overjoyed that the one cell in the center that got left uncolored at the start was the final cell to eventually be colored in at the end!

[@JasperJanssen]

Jeez, spoilers.

[@AndrewMooreMar]

At 2:17:00, Simon decides tthe 4 can't be water, because in that case, the two lose ends of the loop would join having two distinct clues. However, I don't see at this point why the lower end couldn't turn left (to a cell that would be island, to avoid a 2x2) and not break. I'm sure there's something that later disproves that path, but I don't see Simon going through that logic at that moment. Is there anything obvious that I'm missing?

[@DoongXiouHua]

Same here. I think Simon got a bit lucky there.

[@tottle321]

Darn, noticed this too and was hoping there was something I missed. But it seems like it was indeed a logical misstep and luck that it was the wrong path for other reasons

[@yapayzeka3183]

yes i did not get that as well, probably the only step simon overlooks something

[@QonQuest0]

I'm very new to this kind of stuff and i'm not 100% sure i'm making sense, but the top end of the line has to touch the 6 cell island after which it has to touch the question mark below it, which makes the 4 have to be an island, because you can't go from island to island.

[@madeking4]

Yeah. There are 2 or 3 reasons I can see at a glance why that breaks, I don't think he saw them and simply didn't consider he could go through the new island.

[@johnharriman85]

This puzzle fits on a go board, which makes me very happy.

[@six_5000]

At one point, I fell asleep. When I woke up 20 minutes later, Simon was still working on the same loop section 😂

[@skosichm]

Just got to watch this yesterday and today. I was enthralled. Kudos to Simon for sticking to such discipline with logic no matter how tired he was getting. And for such great positivity the whole of the nearly 3 hours. I felt committed to stay with you the whole way. Shame you couldn’t hear me at the end of the video (for several obvious reasons 😂), but I was feverishly pointing at the 10 island that had 11 grey cells. Just one switch to purple and you were done! And to be clear I would have made a mess of this on my own, and I have learned a TON from you about constructing logic around puzzling. Thank you!

[@jimi02468]

It's like a puzzle marathon. It took Simon similar amount of time to solve it as it takes many people to run a marathon.

[@michaelhtritter]

2:44:25 Grateful and glad, indeed. I broke up watching this over 3 sessions across 3 days, and was always anticipatory to get back to it and see its evolution. Brilliant construction and solve. Enjoyed this immensely.

[@ianoz1]

Can't pat myself on the back for this one... made progress, then hit a logic wall... watched Simon up to where I got & moved forward. 17 walls later, I got there, then realised I had a 2x2 in r/c 13/14. D'oh! Amazing puzzle. Really glad I attempted it.

[@valkopuhelin2581]

What a great puzzle! The rules just play so well together with the loop and colors pushing forward together and independently. Wow.

[@turbochrist]

Water clue Couldn't escape if I wanted to Water clue Knowing my fate is to connect the loop Wa-Wa-Wa-Wa-Water clue Finally facing my Water clue

[@myrtinyrtti]

🤣🤣

[@tempota7792]

Only took me 41 bloody hours, but I actually managed to do it. Simon's 9-1 disambiguation start, and my own recognition the the line must loop back thru 1 of the 4 locks, and that the North lock must be the place, helped me to crack this kracken. Very glad I persisted and dug 95% of this out by myself.

[@sh4dowchas3r]

25 mins I'm already yelling at Simon for ignoring the rules. there's a much easier reason for that 1 to not be water, it won't be orthogonally connected to the rest of the water.

[@samspackman8750]

This was scintillating from beginning to end. What a marvel! Great solve Simon!!!

[@sh4dowchas3r]

ah now we know where Simon went on holiday with the colour scheme, it was the Rift Valley where the Flamingoes hang out.

[@brenthooton3412]

Simon characterizes this as being not only just "hard," but "VERY hard" (in all caps) and takes two and a half hours to solve it. For an average solver like me, that means: "Abandon hope all ye who enter"! Or, more likely, "Don't even bother... just sit back and enjoy the show."

[@lavarel]

Probably will be the week's project for me. Slowly finishing alongside the video,

[@danielbriggs991]

Only took me 4:20:09, and some of the sudoku-based puzzles on here take me four times as long they take our associates here in the comments, or I end up unable to finish altogether.

[@MrBlbll]

And what a show it was! Wonderful performance, both from solver and puzzlers.

[@Tof0986]

In fact, it is long, not so hard. I would say I solve 60% of the puzzles of the channel without help, and this one belongs to the 60%.

[@MattYDdraig]

Exactly. There's probably one quite difficult deduction to be made, the rest is stamina. Well worth trying.

[@lisannesibma]

What a lovely puzzle, some beautiful pieces of logic in there! Although the video is very long, there was a really nice flow in it, making it not unpleasant to watch, although I did put it on 1,5 times speed, which I normally don't do for this channel. Very grateful that you showed us this puzzle Simon, thanks to you and the setters!

[@dennisvandok4238]

Normally I would not dare try a puzzle that is ranked 'very hard' and takes Simon over two hours to solve (taken by the lenght of the video). But as soon as the solve started, I realised that I might actually be able to do it. Somehow I find this much easier than Sudoku! Still took me three hours but I never felt that I got stuck. Thank you for this excellent and very enjoyable puzzle.

[@kayleighlehrman9566]

"Do have a go!" he says, with another two and a half hours left in the video

[@michaelmatter1222]

I think he meant GO to the kitchen to get popcorn and lemonade (or other yummy drink)

[@juliedaigle6762]

Wow, what generosity, Simon, to give 2:45 of your day for a solver's birthday and your viewers enjoyment. Thanks, I am in awe.

[@roccov3614]

Crazy that I'm trying this. Making some progress when I realized that the way I'm doing it, the line would have to eventually pass by the outside of one of the 4 areas which is impossible because of the 2x2 water rule. Might have to restart taking more care. Edit: I think I figured it out. There is a clue at the top of the puzzle that could be a 1 sized island and let the loop pass twice. That will make the loop I'm seeing possible.

[@keglitjoreb]

I've tried this a few times myself over the last year or so and kept getting stuck around the 1:05 mark of this video. Great deduction to get to the next steps! What an incredible solve. Psyched to see that CTC gave this a shot so I could see how it's done!

[@sjm6280]

At 2:16:55, why does he say those loop segments must join? That situation can be proven wrong because there wouldn't be enough clues for islands or water segments, but Simon discards that alternative without those considerations

[@MattYDdraig]

69:34 This was an absolute magnum opus of a puzzle. Some incredible logical steps, some beautiful twists, and the lovely way that singular cell in the central area resisted completion until everything else was finished. I've not done a lot of nurikabe before but I doubt I'll see many better in the future.

[@МихаилСвятловский]

Well I risked some hours of my free time and procrastinated somewhat, but I am so proud I finally did it! Thanks for featuring

[@fatemehpezhman]

by just looking at the time, I knew this was going to be a brilliant puzzle!! and truly it was.

[@DekarNL]

I love how this video is 3 hours and I fell asleep after 3 minutes😊

[@mahmoudabdelghany7112]

Keeptng track of the connectivity and getting cues out of that.. brilliant setting!.. a very fitting Saturday puzzle haha

[@iuriikononenko9238]

why there is no statement in the rules regarding the diagonal potency of the loop?

[@angec9908]

“How do I think about this in a way that is sensible?” Sorry Simon, but “sensible” went out the door when you decided water is best represented by purple and land was best represented by gray.

[@rossmcguinn2256]

I haven't watched yet, but after the example puzzle, I was positive Simon would use proper coloring for water and islands. After scrolling down and reading the comments, all hope was lost.

[@dimitrosskrippka2154]

What a puzzle, its so cool trying to deduce something while watching Simon solving

[@HalcyonAcorn]

Alright folks! Get out the popcorn and a couple bottles of wine 🤣 fantastic job Simon!! I really don’t care about the length, I love watching and listening to you solve!

[@megaclpb]

48:34 I love it when it's possible to use the fact that a puzzle only has one solution to solve the puzzle

[@Twiztedgoalie]

Orange or yellow are perfectly good island colors. They can be desert islands. Then you get blue water

[@msgeryjo]

A Simon video is never too long. It pleasurably postpones all the dreary chores (and work) I have to do, love the long ones. Amazing how much angst there is in the comments about the color choices. What cracked me up is that I am sure he has done puzzles in the past that used blue and green. The leopard can indeed change his shorts.

[@angec9908]

Only Simon would use purple to represent water and gray to represent land. 😂

[@Hetpust]

can't you see it? it is obvious

[@zmaj12321]

Duh, the ocean is made out of strawberry lemonade

[@jbruuuu]

I really liked that the very final cell to be coloured is exactly opposite the first cell you are able to colour and start the puzzle with.

[@mwoody_]

One of my favourites that you've showcased on the channel

[@SamAHill]

I was daunted at first, and I felt no shame doing this puzzle along with Simon, but it was incredibly fun all the same, and I did catch a few things before Simon did for which I was rather proud. :) It's the sort of hard puzzle where you can steadily make progress once you get the hang of it. I rather wish I had another puzzle of this same sort I could apply my skills too… Anyway, thank you so much, Simon!

[@princessbenny9909]

So I recognized the name wooferzlg, and it’s cause he developed the Windwaker Randomizer Tracker (Windwaker is a Zelda game set in the great sea dotted with islands) which seems fitting with this puzzle, don’t think it’s a coincidence!

[@Zeher-vy2xo]

I think this is the first time I ever saw how to start a puzzle before Simon did!

[@80fajoogaloo80]

This was a super fun puzzle! I'm still amazed about how powerful the question mark clues were. Haven't started the video yet, but I'm excited to see how long it takes for Simon to realize the loop must go in and out of the channel at the top of the grid. It seemed impossible to break into the puzzle before making that somewhat meta deduction :)

[@ServantOfSatania]

123:15 For me, what a beautiful (and absolutely humongous!) puzzle with some absolute gems of deduction! I can tell the constructors were giggling with glee when they put in that cheeky 13 clue

[@michaellautermilch9185]

21:25 😂 I love that there's no real reason for the color selection, it just obviously should be purple and grey. Ironically everything else in the video is 1000% logical.

[@RecreationallyCynical]

One idea for the solution checker is to have the solver put into the cells that the loop visits (that don't have numbers already) the lengths of the runs in water cells and the sizes of the islands in island cells; if a number is more than 9 use the ones digit. For example, a run of 12 water cells, followed by a 4-large island, followed by 3 water cells, followed by a 5-large island would have "2 2 2 2 2 2 2 2 2 2 2 2 4 3 3 3 5" in the cells on that part of the loop. Cells the loop doesn't visit are left blank. More formally: For each cell that the loop visits that is either blank or has a question mark (ie, no given digits): - if the cell is water put the length of that run of water cells - if the cell is land put the size of the island If the number is larger than 9 put only the ones digit

[@pirukiddingme1908]

“Do have a go” I think I’m more likely to beat Usain Bolt over 100 metres than solve this in less than a week so I’ll just leave it for Simon lol

[@FreakzWasTaken]

How incredible that the area colored at this point in the puzzle (1:17:20) is forming an arrow that points towards the topside canal.

[@wowitscoldout1119]

TWO HOURS FORTY FIVE MINUTES YEAAAAHHHHH‼️‼️‼️‼️

[@alextheshycat]

8 seconds ago holyyyy. and almost three hours long! it's going to be a blast!

[@mritty115]

2:17:00 "And therefore that closes the loop". Why? Why does Simon conclude at that point that the 'bottom' piece of loop *must* continue upwards and not into the land he just put into R16C14?

[@AnteroPedro]

Because that cell would need to connect to the “?” clue that later proved to be water. And as the loop crosses there, it wouldn’t cross the land slightly upwars with the “?”. It wouldn’t have space to go up without crossing the (later) water “?” twice.

[@travisporco]

I know it would be rough to do a mega solve like this every time, but thanks for taking on the heavies now and again!

[@commandercorner5575]

I’m fairly certain you got it right. I got the same solution and watched as you followed the same logic I used.

[@thatonerisottosimp6791]

Wehe thank you so much for the birthday wish!! It's okay you didn't get the email, it happens! I didn''t have chocolate cake but I did have red velvet :3c

[@crazypantaloons]

blue water, greed island, yellow outline of island for sand, red loop (preferrably dotted)

[@AndyStarr0]

a nearly 3-hour video? hell yes guess i know what i'm doing this evening

[@MaierFlorian]

Fascinating puzzle (which I defenitely couldn't do on my own...) - but I have one question: where in the rules is exactly stated that the loop has to move orthogonally? "through the center of cells" can also be achieved by diagonal movement, can't it?

[@pascal6871]

You are right, the rules don't say that. Standard loop rules do say orthogonal which is why Simon thankfully didn't consider it because the puzzle clearly wouldn't be solveable

[@JasperJanssen]

Hell, even by knights move, technically?

[@anaayoung9142]

Lord of the Rings extended version! You are super right. I was very entertained and we have a super satisfying ending when you happily painted the last cell in gray!! 🎉

[@abj136]

Really enjoyed figuring out the crux of this puzzle!

[@AngelWedge]

I allowed myself 20 minutes to attempt the puzzle before watching the video. Just got to 59:00, and I think that's the same point I was up to… but realising I have work to do before midnight. Not sure if I should resume solving or watching when I return.

[@AngelWedge]

(aside from the 2 segment in the top left, and shading 5 cells of the ? island to the bottom right)

[@chadrussell1221]

As someone who has been playing lots of islands of insight, I enjoy these puzzles and am curious if it was an inspiration even for this puzzle.

[@AugustoValentini]

After all these years watching CtC and seeing Simon menting uniqueness I want to see a puzzle where one of the explicit rules is "there is one and only one solution to the puzzle" and where it is necessary at some point during the solve.

[@drlabos]

There was one like that maybe a year ago but I sadly don’t remember the name. It was all about showing how uniqueness works.

[@studgerbil9081]

Both Mark and Simon have stated that they run the puzzles though testers to ensure that a puzzle has a unique solution, but that they cannot use that knowledge alone to disambiguate a specific cell or group of cells; but they must use logic from the rules and clues to do so, the point being that if they cannot do that, then there can be no unique solution based on the rules and clues provided. They honestly have to go into every solve without the knowledge that the puzzle is unique. It's tough to do that. What helps we the viewers is that a puzzle without a unique solution based on the rules and clues will not be shown on this channel. It is a failed puzzle unless the setter specifically states that the puzzle has two solutions (I think I recall one that was specifically set that way).

[@Adramelek14]

@@studgerbil9081there were a few with different difficulties based on the digit the user puts in a cell. So they had 3 different valid solutions

[@ColinKenney]

I am trying to follow the SudokuPad link for this puzzle, but it is giving a 404 error.

[@ukaszk4410]

Same here

[@ChrisLonner]

Great solve. Really long, but great solve !!! Did I miss something, or is there anything in the rules that prevents the loop from moving diagonally from cell to cell?

[@TheMaskedDonut]

This is a nightmarish good time! Great solve!