The Four Types Of Personality

** Today's Sudoku **
Today's puzzle looks impossible - there seems to be next to nothing in the grid... and yet...! It's called X Dots and it's by Nahileon. It's a wonderful and surprising solve. Play the puzzle at the link below:
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Rules:
Normal sudoku rules apply. Each main diagonal (marked in blue) must contain the digits 1 to 9 once each. Cells separated by a black dot must contain digits with a 1:2 ratio. Not all possible dots are given. Clues outside the grid give the sum of the digits along the indicated diagonal. Digits may repeat along such diagonals if allowed by the other rules.
The Phistomefel puzzle called Fillomino Aquarium is available on Logic Masters Germany here:
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Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships.
Thank you for watching!
Simon and Mark

[@Jodawo]

I agree with Simon. At the start, it looks ridiculous that it would have a unique solve. By exploiting the characteristics of Kropki Dots and the use of coloring, it has a logical solve. It's possible, as little as 2 years ago, this puzzle probably too hard of a solve. Sudoku is evolving quickly and it's good to see Simon is still able to keep us from getting lost in the solve.

[@allantidgwell5624]

It's less than 150 years old. It still has a lot of growing to do

[@davidh.4944]

I learned very early on that any sudoku featured here that looks like it can't solve uniquely, always does.

[@allantidgwell5624]

@@davidh.4944 well if it didn't then it wouldn't end up being put up on the channel. It's a matter of survival bias lol

[@qazwiz]

been subbed for 2 or 3 years (feels like was a year before the big C-19 took over our lives so maybe 4 years?) at first it took me 60 minutes to do his 25 minute puzzle and i improved to point i almost tied his time... but since 2x/day the puzzles are harder and i'm questioning both my IQ and often my sanity too

[@qazwiz]

@@davidh.4944 Simon often reminds us he doesn't publish his failures

[@Rubrickety]

This is one of the loveliest puzzles I've managed to solve. I didn't employ Simon's patented "semi-random hybrid color-scheme hodgepodge" method, though, so I think I missed out on some of the fun. 😂

[@furyhunter2909]

Started watching this channel about a week ago and I have to say I absolutely love watching Simon. Seems like he's always happy and he explains his logic very well! Keep it up :D

[@paulparker9593]

I'm really glad you said that - it's exactly the feeling that I had when I started watching 2 years ago. I think the way that Simon goes through the same explanations time after time, with patience and good grace, and in a manner that works for both new and longer term viewers is simply wonderful. I believe that it must be a significant factor in the success of the channel.

[@longwaytotipperary]

Please note: The opening card says this is Sum 41 by Mr. Menace.

[@nahileon1328]

Lovely solve! I hope you enjoyed the slightly more approachable puzzle today.

[@glum_hippo]

The perfect CtC puzzle - extremely elegant but also 'unlikely to work'. Would love to see more like this

[@inspiringsand123]

Rules: 03:49 Let's Get Cracking: 05:19 Puzzle Solved: 42:09 Simon's time: 36m50s What about this video's Top Tier Simarkisms?! Phistomefel: 5x (02:25, 03:09, 03:37, 43:07) Bobbins: 2x (14:13, 14:13) And how about this video's Simarkisms?! Beautiful: 6x (13:55, 17:59, 18:43, 18:45, 24:36, 38:09) By Sudoku: 4x (13:22, 15:55, 25:20, 33:35) Stunning: 4x (39:44, 42:03, 42:58, 43:00) Clever: 3x (12:41, 31:49, 39:49) In Fact: 3x (22:24, 26:00, 42:03) Obviously: 3x (07:00, 14:36, 19:26) Wow: 3x (35:54, 41:51, 41:52) Good Grief: 2x (14:36, 24:36) Sorry: 2x (07:11, 37:52) The Answer is: 2x (23:34, 25:36) Gorgeous: 2x (26:46, 32:03) Hang On: 2x (17:05, 27:06) Progress: 2x (18:11, 42:58) Apologies: 1x (01:23) Lovely: 1x (28:25) Magnificent: 1x (01:29) Surely: 1x (28:14) Think Harder: 1x (34:52) Plonk: 1x (41:25) Most popular number(>9), digit and colour this video: Twelve (6 mentions) Two (104 mentions) Green (31 mentions) Antithesis Battles: High (4) - Low (1) Even (5) - Odd (0) Lowest (2) - Highest (1) 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!

[@LazerWulf]

I've started to notice another Simarkism is "Out of Nowhere" or "Out of Absolutely Nowhere" (17:57)

[@sulimanalzanki9546]

Thsnk you for pointing out the bobbins😁❤️🌹

[@JS...]

Pencil Mark seems to be a new thing, happened couple of times in couple of videos now.

[@roughryder5]

Dude...you need to get out more.

[@joelv4495]

Need to start tracking the pencilMARK jokes lol

[@abj136]

An easier start once you realize what’s going on: Color the dotcells in box 7 red, bllue,green,purple instead of just two colors. This gets you 18 and 24 pairs, and soon the logic will give you blue and yellow cells for 36. Use greys for 579 and soon you’re coloring the whole grid by Sudoku. Then the diagonals decide the values of the cells.

[@therocknrollmillennial535]

57:01 for me, which i find funny because I was finishing the grid with 5-7 pairs. Awesome puzzle, this one was tough for me, I needed the training wheels badly. Hopefully, the repetition of doing these types of puzzles will give me a sort of muscle memory! Thank you, Simon, for the solving help, and thank you, Nahileon, for the great puzzle!

[@clarityc481]

39:11, which I'm very proud of (not as quick as Simon, but shorter than the length of the full video! that's definitely a triumph for me!). I love this sort of puzzle, where it's not about precisely calculating a great many extremely particular sums, it's about shape and matching and then checking those shapes against a few sums. More coloring puzzles for me! Thanks Simon for the fun solve.

[@jasonsampson3379]

Pencil Mark, I'm dying of laughter.

[@federicocucc7852]

Highly recommended this one!!! I actually started this by set theory and almost instantly found the 579 triple in box 5

[@TehFilmFanatic]

Same with me! I tried a few different colouring patterns before I settled after that

[@Ratzfaz]

Set with ''explodet Phistomefel ring'' ? me to

[@KyleBaran90]

Me too! I loved this puzzle and highly recommended it on LMD. Nice to see CTC do it after all

[@RicketyEng]

Yep me too.

[@stegra5960]

Tom Lehrer was the subject of one of the strangest coincidences I've ever known. I wanted to play one of his songs to some friends. I opened the CD player in the campervan to change the CD and in those couple of seconds the radio came on and the 6Music presenter said "...and that song Poisoning Pigeons in the Park..." Yep. The very song I was about to play.

[@marowakcity3727]

I got this one in 40:33 Interestingly my break-in was slightly different than yours, essentially I saw the 4 squares of black-dotted cells as empty rectangles for 5, 7, and 9, because no matter what those digits can't be on a black dot, and used that to place various instances around the grid of cells that had to be 5, 7, or 9. I eventually used the logic that you broke in with, but I think its interesting how we did things in a slightly different order

[@BozoTheBear]

I also started that way.

[@qazwiz]

just seconds before Simon, CONGRATULATIONS !! although, as mr. sand logged, he wouldn't take so long on rules by himself so it's very likely Simon beat you by a minute or so, assuming you started playing as you read the rules. but picky anty aside... CONGRATULATIONS, you more than halved my time

[@DirkieB]

@@qazwiz If you're being picky, Simon spends more time explaining his thought process than actually doing the puzzle, so basically any puzzle video posted, his actual solve time, if left alone, would probably be half the length of the video if not less.

[@qazwiz]

@@DirkieB i know where you're coming from and sure almost every video he (& Mark) will take 60-90 seconds to say 1+2+...+9=45 in a new way (if CTC would sell video Bingo cards instead of a "FREE SPACE" they'd have a "The Secret" in the middle ...) but the longer the video the less extra fluff. do you think he could have done the 2 hour one last weekend in less than 100 minutes? he analyzed it after finishing and if he retried, i'd bet he'd have forgotten so much of the analysis that it'd take more than 90 minutes to repeat. of course it helps that by now he's already solved (or tried) about a dozen other puzzles already. (tests 3-5 of mark's future videos, done 4-5 videos since then, and he's probably done some for fun or even scraped one or two that wasn't up to CTC STANDARDS)

[@kilianheckenberger]

Loved this one! Something about this puzzle went 'click' with my brain and I got through it very smoothly. I think this was my first time solving a puzzle more quickly than Simon did. :o Anyway - thanks for sharing these puzzles, your channel is awesome! :)

[@AlonAltman]

This puzzle has some things in common with my Symmetrio puzzle featured on the channel a few days ago. Specifically the use of black dots and the symmetry 1-8;2-4:3-6, and also the X constraint. Here, however, the symmetry was broken (and 7/5/9 disambiguated) via the little killer clues which are very much not symmetry preserving.

[@Paolo_De_Leva]

That's true. Thanks for pointing this out. I liked Symmetrio a lot and I liked this one as well.

[@martinepstein9826]

Great puzzle. This might be the only time ever that I used Phistomefel's theorem and Simon did not. Those symmetrically placed 2x2s were screaming at me.

[@martinepstein9826]

I resolved the 27 diagonal using parity. Yellow is odd and two of the red digits are the same, so the remaining two digits add to an even number and so must have the same parity. That means they're either 1,3 or 8,6 and it's easy to see 1,3 is too small.

[@rmahu]

Same here. I started with the asymmetric ring and in the end, if I put 1 in the 27 I had an error of 1 and no cell that reduced 1. Then I got the 6 with parity.

[@martinepstein9826]

Just tried this again. Actually, using Simon's insight about 24 going with 36 together with Phistomefel's theorem you can have a nice solve with only two colors; one for the set 123468 and one for the set 579. Then as long as you're diligent about central pencil marks you can color the whole grid while reducing most cells to two candidates, then fill the 27 diagonal, fill the 37 diagonal, and complete the puzzle in no time.

[@markp7262]

34:20 finish. I went crazy with colors and differentiated the 5-7-9s early on. This allowed me to spot the 7s more easily, which then led to 5s and 9s. Fun puzzle!

[@sampathkumar-ej7xl]

I am absolutely amazed at how the setters like Nihileon see patterns in the usual set of numbers and arrange them to create impossible looking grids that have a logical path to solve. A very enjoyable puzzle indeed. I took the same path as Simon except it took me a whole lot more time to get through!!

[@ericpraline1302]

This came together very nicely. At the outset it looked distinctly unpromising, but lo and behold hidden in plain sight was enough information to solve it.

[@grandunification]

This is one of the first of your sudokus I was able to solve without checking the video first! took me ~90 minutes but thats fine, I'm proud of me :)

[@davidh.4944]

68:17 for me. I wasn't originally intending to try this one myself (I really need to do some work tonight), but I watched Simon's opening and realized the logic of the break-in, and ended up playing it to the end. I didn't use colors myself, except in one small section, and it took me a lot longer to resolve both the kropki pairs and the little killer clues, but other than that, I got through it without any major hang-ups. I'm quite surprised at my accomplishment, really.

[@lindsayforestell3621]

Simon just congratulated us on our engagement, my week has been made!

[@bobblebardsley]

There's a kind of exploded Phistomefel thing going on isn't there? e.g. The 2346 black dots in box 9, those same digits appear in row 9 only in the columns that do not contain black dots. It's rotationally symmetrical (e.g. the 1248s in box 7 and column 1) so those kropki 2x2s act like the 16 'corner' digits in a Phistomefel Ring. No idea if that could help with the solution at any point, just slightly surprised Simon didn't mention Phistomefel considering there's an arrangement of 2x2s like that in the grid.

[@Raserei408]

I had the same idea. People sometimes talk about how Phistomefel's theorem applies to the inner, middle, and outer rings, but I've never seen anyone mention (or use) the fact that you can mix-and-match the ring layers on different sides of the puzzle. Re: helping the solve, once you see it, it makes it easier to see that the lower-left cells in the corner boxes are from {1,3,6,8}, one of which Simon's still wondering about 25 minutes in.

[@jez9999]

Yeah, I used that SET to eliminate some numbers in various cells. Assumed the 'broken Phistomefel ring' was part of the intended solve path, actually.

[@Cogskate]

Really nice puzzle. I distinguished the "third yellow" early on, which helped a bit. Otherwise, my solve path was very close to Simon's. I'm quite pleased about that, though it probably owes more to the elegance of the construction than any great brilliance on my part. 😁

[@Paolo_De_Leva]

Some of you found *translational logic* ↘ in this grid, but I don't think this is a complete description of this logic. The puzzle was built by rotating and translating _"kropky structures":_ 🔹Columns 2 and 3 "work" the same as columns 8 and 9 (where the same _"kropky structure"_ is repeated upside down), and 🔹Rows 1 and 2 "work" the same as rows 7 and 8 (where the same _"kropky structure"_ is repeated after rotating it by 180 degrees). Moreover, there is a perfect *rotational symmetry* 🔄 in the disposition of the *kropky dots* around their center of mass (not around the center of the grid)❗ However, the digits that eventually you enter to solve these kropky dots are not rotationally symmetric about that center of mass. Most of them are roto-translated (from box 1 to 9 and from box 3 to 7).

[@Paolo_De_Leva]

Beautiful geometric logic 👏. I agree with *Clarity C:* please give us more of these puzzles that are not based on killer cages and do not require too much ➕➖computational power, but can be solved by studying their amazing geometry, which in this case was forming a magic lattice of connections throughout the grid.

[@Paolo_De_Leva]

👏 to the magician Nahileon

[@anjaschneider5904]

Wow. Just wow. I needed a little hint from Simon to start with, but from "color them in" on I did it all on my own:))))) Max and min and mod 3 in the diagonals :) I just love this channel!!

[@RicketyEng]

I started with immediately noticing how the black dot squares interacted with where 579 could go in those boxes and I drew up a set of set logic. It helped me further restrict 579 and also keep them in mind. I had nearly the whole puzzle filled with 18, 24, 36, 579 before I felt the need to start disambiguating it and that is when I started colouring (knowing all along that's where it was going).

[@Sylvester.vanWelij]

For distinguishing the parts of a pair it would be clearer not to use two colors, because it exhausts colours quickly. A better scheme would be to use just one color and add different greys. So instead of green/purple one would use green-grey/green-black. This way one does not need to remember which colors form the pair. This method can also be used for triples: yellow-lightgrey/yellow-darkgrey/yellow-black.

[@piarittersporn]

Because the 3 and the 6 always had to be placed horizontal on the black dots and I chose for the pairs of 1,2,4 and 8 intuitivly the correct places - as they seemed most likely to me - I could work with the diagonals and the two outer totals very well to place or exclude the missing numbers step by step. A great puzzle.

[@LednacekZ]

playing with area logic, found something not sure it would be useful during solve. If we make columns 2,3,8 and 9 blue, and rows 3,4,5,6 and 9 orange. Remove shared squares, and the extra orange row which can be substituted by orange box5 ( same 1-9 ). We end up with just the black doted pairs in corners in blue and a weird interrupted square shape in orange. And we know what numbers are in in orange now.

[@minamagdy4126]

that is a variant of what is called an exploded Phistomefel ring. It's like the Phistomefel ring, except it uses different rows and columns, ending up in a different 4-orb pattern and fragments of the ring alongside the orbs

[@olivier2553]

That is very elegant!

[@BozoTheBear]

oh, very nice! i started by thinking about 579-s, and soon enough eliminated 579-s from the squares that end up orange in your colouring - you've found a really elegant way to jump right to that realisation!

[@qazwiz]

you found a way Simon could've made video 5 minutes longer to explain the exploded Phistomefel ring, so shhh, don't tell Simon he F-ed up LOL

[@LednacekZ]

@@qazwiz he loves to explain the Phistomefel ring.

[@davidhughes7174]

Chromatically beautiful. Another wonderful puzzle and solve. well done.

[@lomax343]

The four types of personality are: 1) The glass is half full. 2) The glass is half empty. 3) It's half full. No wait, it's half empty. No wait ... what was the question again? 4) Hey, I ordered a cheeseburger.

[@germax]

This is better than netflix to keep me engaged for hours

[@Paul-cn3ij]

Always love a good colouring puzzle. Very happy with 30:46. Now to watch the video and see how I could have improved.

[@rahkshirock96]

its interesting to solve the puzzle using set theory, and have it be pretty useful, and then see the route that doesn't require it. gorgeous puzzle!

[@wariolandgoldpiramid]

This was beautiful, I loved the logical path. And coloring is always so satisfying :D

[@adnagapot]

I really enjoyed this one, the trick to row 5 finishing the puzzle really shows how a fast solve comes from looking at the right place at the right time

[@DonaldSjervenE]

This one has me hooked. I can't think of a reason why 579 can't be pencil marked in the center box right away. These 3 digits should be on the same diagonal in box 5 too, I think. Reference Mark's solve of Super Symmetry. The digits 579 in box 5 are on the same diagonal. Furthermore, the corresponding 37 and 27 diagonals have exactly the same composition. 4 of the ratio numbers (123468) with the rest being digits from 579. Both you and Mark solved the same puzzle! Rules were different but the puzzles were the same. Deja vu.

[@jacobknight5497]

SUCH a beautiful puzzle, thank you so much!!

[@borisgrozev2289]

I really enjoyed this one (it's one of the harder ones I've done). The start was difficult, and then it just kept unraveling steadily. It's super impressive that someone can set a puzzle like that!

[@PathOfShrines]

Fun puzzle. The break-in is quite clever, and then the propagation is surprisingly interesting. 28:58

[@longwaytotipperary]

I enjoy the "Sudoku quilts" that suddenly resolve all at once - like a magic trick! 🤗

[@elliottmanley5182]

I've been thinking this for a while, but this puzzle shouts it more strongly that any other I've watched on the channel: Sven needs to add non-numeric placemarkers, probably the letters A-I.

[@robert-skibelo]

I couldn't agree more. While the software has improved a lot over the last year it still surprises me by lacking features I would have considered obviously essential. Your suggestion is one. Apart from that the small selection of available colours is surprising, since it would be easy to add a few more. The cells outside the grid need to be able to be coloured and edited: in a recent puzzle where clues composed of O's and E's were written outside the grid Simon was greatly hindered by not being able to in some way mark the ones he had used up. And in some puzzles involving cell arithmetic a scratch pad is needed so that (a) Simon doesn't repeatedly lose time by forgetting what he calculated ten minutes ago and (b) viewers can refer to his calculations when following the solve.

[@Jaxom35x]

I almost got this totally by myself. Found the break in and got quite far, but was lost until Simon mentioned that 2 of the 3/6 trio in the little killer were the same because of looking at an unrelated 3/6 cell. From there it was all downhill. This was a great one.

[@boladuxo]

I really enjoyed that by 31:00 we still don't have a single digit, but already have so much information

[@Tepalus]

Well... I solved the 2h puzzle from yesterday in under an hour, but had 2h for this one that took you under an hour. Perfect balance. 👍🏼

[@Gonzalo_Garcia_]

19:42 for me. Quite impressive that this puzzle has a unique solution considering how the initial grid looks. Great puzzle!!

[@Felixkeeg]

107:32 Quite tricky. Didn't come up with the most elegant way to solve it, but nevertheless made it.

[@AussieJohnny]

My break-in was similar to Simon's. I looked at the downward pointing kropkis in box 3 and realised neither could be 3:6 because that would stop 3:6 in boxes 6 and 9 and you would need 5 occurrences of 1,2,4,8 in the other column 8 or 9. I was concerned for a second or two when Simon put 2/4 in r7c5 and I had a 6...but then Simon quickly realised the symmetry to row 3 was row 9, not row 7. A brilliant but still approachable puzzle. Thank you CTC and Nahileon.

[@CauchyIntegralFormula]

31'36". As soon as I realized that the only thing distinguishing 1-2 from 8-4, 3 from 6, and 5, 7, and 9 from each other were the diagonal clues, I switched to coloring and things got way easier

[@crystalgehrt8861]

This puzzle is insane, unlikely, impossible, and fun!

[@solfeinberg437]

Couldn't've done it without multiple hints from Simon, but had some ideas about the initial pairs on my own. 36 & 24 had to go together and 1248 had to go opposite. Initially I just came up with a possible configuration of the black dot pairs. Then I had to go to Simon, multiple times to get hints to fill it in. Once I had his ideas, I could complete the puzzle. Nice one, but still very far from being able to do these by myself. Or at least, I got to where it wasn't fun to think about and I had no new ideas. Maybe eventually over days, but even then.

[@cheezunriceramen8995]

OMG Simon. 37:00 Scan the grid. You've been called on it for so long now. Just do it. You've got purples and greens just sitting there. Use them.

[@LavenderGooms]

First time i've done one of these puzzles and completed it without checking the video to see what i'm missing. Took me two hours but it was fun.

[@DarkChasm]

fantasticly cool concept, excellent work, love it :)💖💖

[@Torisson]

To start, not knowing what to do, I wanted to see what something would look like that failed. So I picked some numbers for each of the dots. And filled in most of the grid. But I couldn't find a contradiction with what I was doing and knew I hadn't ruled out other good options. Fired up the video, jumped near the end - none of my guesses were wrong. Oops. Didn't learn anything that way, though. Skipped around in the video a bit to get some idea of how to work the puzzle, and decided to try it from scratch with some ideas of where Simon went, but without having watched him really get going. Did manage to work through but I don't know if I could've ever gotten there without some help, especially starting off so strangely.

[@jaeusa160]

@10:30 Is it possible to narrow the black dots in boxes 4 and 6 to 3+6 from this very early point? What I'm noticing is no matter how they're arrayed, if box 4 or 6 contain any variation of 1+2 2+4 or 4+8, it makes for an impossibility in the columns. In box 7, for example, even if one of the dominoes is a 3+6 (let's say purple), and box 4's is blue, then green has to contain NO repeat digits from the blue domino. So one would be 1+2 and the other 4+8. But then what does orange become? It could not be 2+4 as it would see both a 2 or 4 within its box and column. It gets even worse if you tried to say 3+6 was orange in my example and it would force green+purple to be the same pair of digits.

[@erickehr4475]

I solved this in 30:26. There were quite a few bits of clever logic in this one. It was interesting how (in my solve at least - I’ve not yet watched the video) each little killer clue was solved uniquely in a fairly simple way despite there seemingly being many options, by various parity/modular arithmetic tricks.

[@Raven-Creations]

Excellent puzzle. It wasn't at all symmetrical, but it was close enough to be able to apply the same logic. Thinking that it was symmetrical was dangerous and nearly got you into trouble. Your colouring scheme let you down. Although it was useful at the start, once you had identified which pairs were 36s, you needed to colour individual cells to be able to easily see what was going on. When you recoloured the 24s, this was a mistake. For instance, both purple and green 18s are associated with an orange 24, but if you had a purple 24 and a green 24, you'd know which 24 you were looking at. The diagonals and dots meant that it was then easy to colour the whole grid (although I didn't colour the 579s). I liked the way that each diagonal only partially resolved the colouring. Often in this sort of puzzle, they remain unresolved until one clue disambiguates them all, whereas here it was necessary to use one to resolve some of the colours, and then apply that knowledge to the other diagonal to complete the resolution. I also liked the not-quite-symmetrical construction, which avoided needing extra clues to break the symmetry.

[@goonybl]

Those 57 and 9s were beautiful

[@Hertog_von_Berkshire]

A "Poisoning Pigeons in the Park" sudoku would be cool. 😎🐣

[@CMLachky]

Great Puzzle!! Very cool logic!

[@blomman1719]

Managed it in 48:31, usualy I can't solve these so I'm happy.

[@DonaldSjervenE]

Well done! Guessing 5 in the center was based on 37 needing a 79 so 4 of its 6 digits must be "ratio" numbers. Right? The corollary is 4 "ratio numbers" in 27. Does it need a 9 in its 5 digits? I may never be a great solver but I like the way my intuition is getting trained from these videos.

[@th.nd.r]

I about lost my marbles at the 36 pair on the positive diagonal. That’s incredible. I’ll update this comment with my thoughts as I continue watching. EDIT 1: what a unique symmetry in this design! So cool! FINAL EDIT: Just incredible. Every deduction was splendid. Well done on the setting Nahileon, that’s so cool, and well done on the solving Simon, impressive/eloquent/humorous as always! Can’t wait for the Metallica cover! FINAL final edit lol: yeah, the fact that grid solves is incredible. That’s a masterpiece.

[@AlexanderDaniel]

i love the colouring ones !!!!

[@christinemenard1412]

You love your symmetry... Almost as much as your Srabble tiles ! This grid is made of translations... I thought about "corresponding angles", or corresponding cells. As usual, nice solve Simon. I did it in 50 minutes!

[@Xiuhtec]

I came to the conclusion the box 3 and 7 dots couldn't have 3-6 in a slightly different way since I didn't see the 2-4 corner markings as soon. If either domino of those is 3-6 it rules 3-6 out of all 4 other dots it "sees" leaving a 1248 quintuple in the other column one digit short of being completable.

[@Rmifaabsbb1]

In the beginning 36 can't be in the purple or green cells, because it eliminates 36s from orange and blue and that would put 1248 into five cells in the neighbouring column to the 36 pair

[@bobblebardsley]

This really felt like 81 little boxes wrapped in layer upon layer of coloured tissue paper, and watching Simon unwrap layers from all the little boxes to find the number hidden inside. I've a feeling I'm going to see a lot of sudokus in that sense in future, but I've never felt that way about one before.

[@TurquoizeGoldscraper]

39:30 for me - Took me 30 minutes to get a single number in after a lot of coloring, and then it started to come together.

[@bkaozzz]

I'm so happy I solved this puzzle! Wouldn't have been able to do it a couple of months ago, and in 27:17 Loved every minute of it!

[@Tfin]

I got the dominoes in boxes 4 and 6 easily enough, but it took a long time to get to the point where the 27 LK did anything. By then I had already marked 3 and 6 with different colors, and after filling in all the 579s, the 1248s got 4 colors.

[@KeithGrant]

There's something so satisfying about coloring the whole grid before placing all the digits in a mad frenzy. took me 33:35

[@tanitabaumgartner2089]

My favorite part is when he finally removes the black flash at the end

[@Paolo_De_Leva]

I love😍colouring, but I think in this case it is a *waste of time.* Only two cells are meant to be coloured with the same colour, but you can easily avoid it, because immediately after realizing that they must have the same value (either 3 or 6) you can find that value (3), by solving the 27 diagonal: *r1c5* and *r3c7.* These two cells are very easy to find, as they are clearly needed to solve the 27 diagonal. Simon coloured them in red at playback time 30:17.

[@LithmusEarth]

21 Minutes in: you can differentiate the colors in box 3 now, It's the Purple 24 on the diagonal and the Green 18. so Purple in Column 8, Green in Column 9. 25 Minutes in, you colored the 18s, but through entirely different means. 30 Minutes in, Look at Row 5. C1: 24 Orange; C2: 18 Purple. C7: 24 Orange; C8: 18 Green from there... C2,R4 Yellow // C6,R8 Yellow. Then I think it ends up Being a deadly Pattern with the four remaining spots, which something else will disambiguate. 36 minutes in, he finds the start of it he gets row 5 done.

[@DonaldSjervenE]

Curious. Two puzzles in as many days that are similar. Pencil Mark had a 7 in the center cell. But here there are no clues on the 5/7/9 except the 37 diagonal which needs a 7 and 9. So I will guess 5 in the center cell. Now on to watching the master solve. (Seems like a clever side game can be played with Sudoku. Pick a cell and make a guess.)

[@LednacekZ]

40:29 today. Could have been faster, but i forgot that one of the blue/orange pairs is 24 and those are numbers from green/purple pairs. I was so happy when i found it out and immediately disappointed of myself that i had to find out something i already should have known from the beginning.

[@HunterJE]

Am I seeing things wrong or could purple/green in box three have been differentiated much earlier using the diagonal as soon as the 2x2s were narrowed to their 18/24 pairs?

[@awilliams1701]

you're not wrong. He missed it.

[@Nerdnumberone]

I believe switching all 2/4 cells orange was a bad idea since being able to differentiate purple 2/4s and green 2/4s had value and most of his 2/4s could be colored all the way back when her decided to recolor them to orange (also the 1/8s through the diagonal).

[@jonasbranstrom5323]

Oh please release that phistomefel video :)

[@stephenbrownca]

Solved in about 55 mins. Haven't watched Simon's solve yet, didn't use any special tricks. Just a little bit of coloring and deduction on the possible values of kropkis.

[@francoisduez601]

26:50 using mostly Simon's tricks, including colours of course ;)

[@SapioTV]

37:19. Very fun solve!

[@eduardos4607]

The moment you realize that a set of all of the 4 black dot possibilities contains two 2s and two 4s you get an X wing on 2s and 4s. Then it becomes very solvable.

[@mirekchytil903]

It looks hard, but I had one of my best (shortest) times :) And I do not usually manage to finish the puzzles of such video length on my own. The (initial) coloring was ridiculous :D Should be dumped right after filling the square areas with quadruplets or at least pairs. But the corrected coloring did some help. I on the other hand id not color (just the kropki dot areas with one color), and used more central pencil Marks :D

[@justinaclayburn2248]

I was so proud of myself because I figured out the 2/4 limitation before Simon.

[@justinaclayburn2248]

Mostly because so often Simon is like “obviously” and I’m like… wha????

[@qazwiz]

SETTER REQUEST: title "nothing matters" where zero digits as clue so maybe some sandwich clues WHERE 1 and 9 next to each OR 0 from that x,y thing that mark solved one or two days ago. maybe even a third possible rule where need to decide which zero clue decides which rule applied used ? NEEDED BEFORE SIMON FINISHES THE MUSIC HE SAID HE'S PRACTICING (today's January 18, 2022 puzzle aka "The Four Types Of Personality")

[@Culpride]

Is it me (because i tend to be good with colours), or did simon manage to bridle this horse from the hooves? Very entertaining video, fantastic puzzle.

[@AndreAy1975]

Solved it with help from the video.

[@JoyanneBecker]

Well, if you wanted to know how long it takes a total noob to do this without any idea where to start, it took me around 1:57:00 😅😅😅 Hope that makes someone feel better! Lots of scribbling down sums and switching to the calculator app. Now to see how to actually do it..

[@JoyanneBecker]

Ahh yeah I think my problem was that I completely overpolluted the coloring system, it made finding sudokus so much more tortuous

[@OverkillSD]

The title card threw me off - I was like "Didn't you just do Sum 41 in another video?!"

[@MasterKnightDH]

About the 27 Killer, I actually realized that the 2 non 3s/6s had to add up to a multiple of 3 because the 3s/6s did so themselves. But yeah, coloring is useful in general nevertheless.

[@scodavis]

Major LOL at "Pencil Mark"

[@shteevuk]

This was fun!

[@srwapo]

41:16, but I needed to see how to start.

[@jamessweatt985]

29:05 for 43 seconds, Simon's scanning takes a holiday (or "vacation" as we say in the U.S.). In succession, he finds two different dominoes that must each contain one yellow; those are easily colored and makes his next step easier. He gets there later. Great solve of a surprising puzzle, Simon!