The Miracle Sudoku [video]

https://www.youtube.com/watch?v=yKf9aUIxdb4

by eigen-vector • 6 years ago

596 143 6 years ago

youtube.com

acangiano• 6 years ago

25 minutes you'll be okay with never getting back.

jurmous• 6 years ago

You can also if you want turn the playback rate up of the video and have the same satisfaction in half the time :)

the_duke• 6 years ago

I recently started increasing playback speed on many videos I watch. It's really hard at first, but I quickly got used to it, to the point where I now use an addon to increase playback speed to 3-6x where appropriate.

When there's something complicated, or something I want to enjoy and savior, I jump back and slow down.

This is an incredible time saver.

I got inspired to do this by observing a blind programmer use a screen reader with insane speeds.

yesenadam3• 6 years ago

Really, you can follow his explanations at 2x?! Less than 1x the satisfaction, I suspect.

singlow• 6 years ago

Been addicted to this channel since the lockdown started. Many more than 25 minutes I'm happy to be rid of.

CamperBob2• 6 years ago

Once you see that each row appears to be a shifted copy of the same sequence, you'll spend at least part of that time yelling at the screen, hoping he hears you.

matsemann6• 6 years ago

In fact, all rows are just permutations of the numbers 1-9! Edit: ;)

glenvdb• 6 years ago

My favourite part is his own disbelief as he ... spoiler ... continues to solve it.

A few minutes later... when the first three on the board causes a cascade of solvable cells after a build up of deduction. Amazing.

accidentalrebel• 6 years ago

He also said he was closed to ending the recording because he thought he was being trolled by the creator.

It was fun seeing him slowly realize that it was not a joke at all.

msoucy• 6 years ago

I once spent an hour trying to solve a sudoku puzzle on a whiteboard in college. It turned out that the person who left it there made a mistake when they started to solve it, so given the state it was in when I started (no way to tell what was original and what was their deduction) it was impossible to solve.

I'm not bitter, of course not.

this_is_not_you• 6 years ago

Now I want a making-of video by the creator of the Sudoku.

redcodenl2• 6 years ago

I wonder how much of that is programmed/automated and how much work is still being done manually...

Backtracking and eliminating numbers can be easily automated.

Fiahil• 6 years ago

I made a sudoku solver back when I was in school. It's quite simple and almost a textbook case for backtracking. Even brute-force algorithms are instantaneous on the hardest puzzles.

SubiculumCode5• 6 years ago

As a college project in C, we were to write a soduku solver. Smart people solved it by programming in fancy heuristics. Not being smart, I just brute forced it...though I tried to be fancy by representing the data at the bit level. I doubt it made it any faster lol.

That said, when the hardest Soduku problems in the world succumbed to a brute force search to my lame program in less than a few something something ms, I kind of shrugged at the fancy methods. But I suppose that is why I'm still just a mediocre programmer :)

The brute force method was basically move forward until you hit a dead end, backtrack, go forward again until you hit another dead end, etc.

Edit: I'm not being dismissive of people who implemented better solutions. Honestly, at the time I was amazed at their skill. But I still chuckle just because the problem is trivially sized for brute force methods, and would have to be scaled much larger to actually make more sophisticated methods worth the effort in any situation other than personal satisfaction and education. In a business situation in which you do not expect the problem to scale, spending more time for a sophisticated solver may not be worth the effort. But yes, Soduku is for entertainment and R&R

shultays4• 6 years ago

I was discussing this with a friend. I too made a brute force sudoku solver. It was somewhat smart since it was keeping track of what options are available for each cell and updates those options as it puts/removes digits.

The friend told me he was working on a sudoku solver and was trying to explain his non-brute force algorithm. I told him I did a solver back in collage and it was basically instant even though it is brute force.

SubiculumCode5• 6 years ago

Amazing. I got down voted for my story. HackerNews does not like Mediocre Programmers I guess lol.

I bet I could write a better algorithm today if I was motivated. Back then I was not as experienced in programming, and I struggled with even figuring out how to represent the data and the state. Its all about learning from where you were at the time.

twic• 6 years ago

Similar story. A friend and i were arguing about whether you could solve sudokus by brute force in reasonable time. So we whipped out a couple of laptops and tried it. I had a brute force solver (kind of branch-and-bound-ish, ISTR) finished before he had his constraint-based approach running, and it solved any puzzle in the blink of an eye.

To capture some of the fun of human Sudoku-solving, i think you'd want to have some sort of metric for how brute the force is, and then see if you can write a solver which is as unbrutal as possible. I'm not sure what that metric would be, though.

goto11• 6 years ago

Wouldn't brute force be enumerating all possible combinations of numbers until you find one where all sums are correct? Your approach with backtracking sounds more fancy

SubiculumCode5• 6 years ago

It was a long time ago, but I think I randomly filled in numbers, save if numbers were already used in each row or column, then when it reached an impossible solution, it would work backwards one level, trying new numbers. If it ran out of numbers, it would go back two columns, and try a new number.

I doubt it was anything fancy. At the time, it bent my mind into knots. Programming is a wonderful mind trainer.

mikejb• 6 years ago

when the hardest Soduku problems in the world succumbed to a brute force search to my lame program in less than a few something something ms, I kind of shrugged at the fancy methods.

I think you're coming off as dismissive, which is why you're getting downvoted. Puzzles like these have the purpose to entertain a human solving them, and they do that pretty well.

If you seek entertainment in developing algorithms to solve these puzzles, you should adjust your challenge to modern computers: Up the size to 100x100 or more, see how your algorithm performs, and go from there. Spoiler: NxN Sudoku is NP-hard (NP-complete, to be precise), so have fun - maybe you'll even win a million dollars.

Now, if you want to really challenge yourself: Write an algorithm to create Sudoku puzzles that have a unique solution and as few initial numbers set as possible. Maybe you'll even improve your coding skills beyond mediocre. ;)

SubiculumCode5• 6 years ago

Good point. Thanks for bringing that up. I've edited my comment to bring context to my perspective.

jmiskovic• 6 years ago

The lightning speed of his observing standard rules across the board is impressive but expected after months of practice. The agility with which he picks up new rules and starts working with them is sign of a beautiful mind. This was a pleasure to watch.

ace32229• 6 years ago

Decades of practice in fact

shultays4• 6 years ago

Yeah, the guy is a genius at solving sudokus and makes it look easy. It is amazing how he fast can develop new "algorithms" and the explanation for the for new rules he encounters. And the way he develops/explains those algorithms

dan-robertson2• 6 years ago

I though that too at first but actually they seem well practiced too. Eg other sudoku-style puzzles also have knight move rules. The main trick I missed is the forking one (if I put a 3 here then it reaches here and here by knight’s move therefore it can’t go here).

That said It is still impressive and I think practice is not sufficient to explain how fast he is at it.

ghusbands• 6 years ago

(if I put a 3 here then it reaches here and here by knight’s move therefore it can’t go here)

A possibly-simpler way to look at it is the inverse. Putting a 3 here or here (where it must go) both block this other place, so we know this other place is blocked either way.

andrelaszlo• 6 years ago

It's really impressive to me how clearly he articulates what is going on in his head while solving.

techslave• 6 years ago

that’s my favorite part. not that he can solve it, but that he articulates the process, seemingly at full speed and totally relaxed.

reminds me of race car drivers that do live narration

jgwil2• 6 years ago

Yes! Bet he would ace whiteboard interviews too.

js2• 6 years ago

"Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."

Impressive work from a board that initially appears too open-ended to solve but turns out to have sufficient constraints.

Well worth watching. (Aside: the solver reminded me oddly of Professor Falcon.)

andretti1977• 6 years ago

Oh my gosh Professor Falcon!!! You reminded me of those times when as a kid i wad so excited and inspired by that movie!

aidos• 6 years ago

I almost didn’t watch that’s because who cares about someone solving a sudoku puzzle, but that was brilliant.

That’s one happy solver; it was worth it just for the absolute joy he gets from it. Amazingly quick solving too. Good to watch him develop extra strategies during the process.

matsemann6• 6 years ago

Yeah, I liked how he realized two possibilities for a number that were next to each other, also meant the box around it could be cleared.

I really enjoy finding patterns like these in constraint games. After confirming the pattern for myself a number of times, the brain later just does it on autopilot. If people have tips for similar games I would be happy to try them.

Edit, my tips: Simon Tatham's Puzzle Collection [0] has lots of them. Apps exists for mobile devices as well. Everett Caser [1] also have lots of logic games where one can learn patterns. I've played Sherlock and Honeycomb, and my favorite is Willa's Walk. They look a bit funky, but the apps work fine on Android.

[0] https://www.chiark.greenend.org.uk/~sgtatham/puzzles/ [1]: http://www.kaser.com/ww.html

ZeroGravitas• 6 years ago

There's a book called "Puzzle Ninja: Pit Your Wits Against The Japanese Puzzle Masters" that covers these strategies for a bunch of similar games, as well as background info on the creators and examples of the puzzle try.

However, I've found that discovering these strategies myself is actually the bit I like most, so although I've bought the book, I try not to read about the strategies I haven't figured out by myself.

panzerklein• 6 years ago

Picross 3D is amazing. Should run without any problems on emulator.

chris_st2• 6 years ago

I'll second Kaser's "Sherlock"... Had a lot of fun with that back when I had a windows box.

And YEAH, his art-style is funky indeed!

kadoban2• 6 years ago

If you're into that feeling, learning a game like go might be something you'd enjoy. There's other parts to the game, but finding clever tactical moves is a huge rush of that.

There's also books and sites with "go problems", chosen puzzle positions, for a quick fix (but only after you know the game a bit).

frankmcsherry• 6 years ago

Yeah, I liked how he realized two possibilities for a number that were next to each other, also meant the box around it could be cleared.

This struck me as a bit weird (as he's clearly 100% sharp): this is just the application of the same rule he had been applying everywhere else: if a number can be in one of two squares than anything that can reach those two by king or knight cannot be correct. He doesn't need to use speculation about which of the two cells it is in.

cbsks• 6 years ago

I am a huge fan of Simon Tatham's puzzles. His developer documentation [0] is absolutely amazing. All the puzzles are written in very high quality C with, in my opinion, a perfect ratio of comments to code [1].

I was hooked on his Tents [2] puzzle for a few weeks, then I started modifying the code to automatically fill in squares based on the tricks I found for adding constraints. Before I knew it, I had written a complete solver! Now I don't have to waste my time on it and I can get back to work :)

[0] https://www.chiark.greenend.org.uk/~sgtatham/puzzles/devel/

[1] https://git.tartarus.org/?p=simon/puzzles.git;a=blob;f=tents...

[2] https://www.chiark.greenend.org.uk/~sgtatham/puzzles/js/tent...

mft_• 6 years ago

Agree! I was very sceptical even opening the video. And then, 25 minutes later…

andrepd• 6 years ago

Yeah all of his videos are great, in a wholesome kind of way.

leetbulb• 6 years ago

I discovered this channel with the four digit magic square[0]

When I first saw that video, I thought the same thing and just brushed it to the side. Later that day, SO and I were bored so I figured I'd toss it on the TV. Immediately she wanted to solve it with me before he started to explain his solution. Now we do these together every so often and compare strategies. Sudoku can be a good partner exercise, too :)

[0] https://www.youtube.com/watch?v=hAyZ9K2EBF0

AS126• 6 years ago

Now I have to watch it... God damn it! Because your comment I mean.

zwegner• 6 years ago

In case anybody sees this comment before the video: I'd highly recommend trying to solve the puzzle yourself. After you see the rules stated in the video, click the link in the info. It took me a bit longer than this guy, but it was a very fun puzzle.

prawn2• 6 years ago

Absolutely agree. When he was about to start the threes, I stopped watching and saved it to solve with my 7yo that night. My son was the one that got most of the three placements ruled out and enjoyed lording that over me. After completing it, we went back to watch the host solve it. Fun puzzle and just as entertaining watching the host gradually put it together himself.

vesinisa• 6 years ago

So to reiterate, this is not solvable by normal sudoku rules alone. Further rules and constraints are provided on the placement of the digits that happen to render it solvable.

thom4• 6 years ago

I'd never done sudoku before and was a little disappointed to find it was so mechanistic. I'd sort of expected there to be some degree of exploration and backtracking, or perhaps having to solve multiple digits simultaneously while attempting to keep it all in your head. Is this puzzle representative of normal sudoku puzzles or do the additional constraints change it?

graywh• 6 years ago

extensive "exploration and backtracking" (what the community calls bifurcation) is generally avoided when setting puzzles

there are more advanced patterns and techniques that can be used with sudoku, but this puzzle doesn't feature all of them

rtpg• 6 years ago

Basically the challenge is in finding the thought process that leads you to an answer.

The kinds of puzzles done on this channel tend to be pretty tough. the designers of the puzzle usually make it so that there's really one good path for solving (and brute forcing _really doesn't work_ relative to thinking hard about the problem).

There's a lot of stuff going on in this puzzle that's not at all present in normal sudoku, and things like "OK let's try and look for where _all the 3s could be at once_" is easier said than done.

kccqzy• 6 years ago

On the other hand, backtracking feels much more mechanistic to me. A dumb computer can guess and backtrack and check constraints with a simple algorithm. Humans ought to do better than that—with more logic and more deduction.

darekkay• 6 years ago

Check out a Hitori. It's kind of an "inverse Sudoku". More difficult puzzles always get to a point where you have to guess the state of a certain field and then backtrack if you were wrong.

chrisshroba• 6 years ago

Does anyone know of good places to look for similarly interesting puzzles? I'd recommend https://puzzling.stackexchange.com/ but I'm looking for others to supplement that!

louisch• 6 years ago

Ever since seeing this video I've been wondering if there's some deeper mathematical basis for this puzzle, because of the extremely regular pattern that it happens to produce.

For example, the way consecutive digits are actually in order, but separated by a single square (and looping around the edge of the board)

macintux2• 6 years ago

See this thread (disclaimer: I have zero clue to its accuracy).

https://twitter.com/NikhilBukowski/status/126262285333933670...

jianshen• 6 years ago

There is something irreplaceable about the first time you solve a difficult puzzle, especially one that you anticipate to be daunting. As a Sudoku enthusiast (though not at Simon's level) this was surprisingly vicarious to watch for what's usually a silent solitaire experience. Well done!

mywacaday• 6 years ago

and we have rotational symmetry! brilliant!

deepaksurti• 6 years ago

Using my CL based sudoku solver [1], I got the following solution. The solution is valid but different from what is shown in the video. IIRC, a sudoku board can have multiple solutions but anyone out here can explain why so? I am no sudoku expert or enjoying solving sudokus anyways!

[1] https://github.com/dmsurti/sudoku

```

(setf board

      #(0 0 0 0 0 0 0 0 0

        0 0 0 0 0 0 0 0 0

        0 0 0 0 0 0 0 0 0

        0 0 0 0 0 0 0 0 0

        0 0 1 0 0 0 0 0 0

        0 0 0 0 0 0 2 0 0

        0 0 0 0 0 0 0 0 0

        0 0 0 0 0 0 0 0 0

        0 0 0 0 0 0 0 0 0))

```

* (sudoku:print-board (sudoku:solve board))

1 2 5 | 6 4 7 | 8 9 3

8 3 4 | 5 9 1 | 6 7 2

9 7 6 | 3 2 8 | 4 5 1

- - - - - - - - - - -

5 8 9 | 2 3 4 | 1 6 7

2 6 1 | 7 8 9 | 3 4 5

3 4 7 | 1 5 6 | 2 8 9

- - - - - - - - - - -

4 9 2 | 8 1 5 | 7 3 6

6 1 8 | 9 7 3 | 5 2 4

7 5 3 | 4 6 2 | 9 1 8

```

edit: formatting

hummusandsushi2• 6 years ago

Your solution doesn't respect the knight's move and king's move constraints, which cause the original puzzle to have exactly one solution.

Marazan3• 6 years ago

You have consecutive numbers appearing next to each other.

One of the constraints is that no consecutive numbers can appear orthogonally.

This isn't a standard sudoku, there are extra rules. There would be a huge number of valid solutions to the board under regular sudoku rules.

EDIT: and you've missed the King's move constraint as well and I presume the Knight's move as well.

prawn2• 6 years ago

The first line of your result fails the orthogonal adjacent rule of this puzzle eight times!

boomlinde• 6 years ago

Your sudoku solver is solving a different puzzle altogether from the one posed in the video. Sudoku puzzles also don't normally have multiple solutions. The smallest known Sudoku satisfying that constraint have 17 clues. Offering only two clues is possible here because of the additional placement constraints.

tudorizer• 6 years ago

Not a big sudoku fan, but wow! I might have under-estimated how exciting it can be.

Jestar342• 6 years ago

This guys is my "ASMR" bedtime watching. I just love his overall demeanor and child-like thrill from puzzle solving. I can be wired when I start his video and by the end I'll be blissfully calm and head-clear. I think he has a tremendous talent of focus. As other posters have said, he can spot constraints so quickly. I still get a small kick out of spotting something before he does, though. Doesn't happen often, mind.

pilsetnieks• 6 years ago

I actually had to double check if Sean Lock (https://en.wikipedia.org/wiki/Sean_Lock) hadn't taken up a new hobby of solving sudokus on youtube, he both looks and sounds incredibly similar.

fredley• 6 years ago

How on earth do you create a puzzle like that? Coming up with the rules it's presumably simple to generate solutions with a computer program, but how do you then work out the cells which need to be filled in order to not only minimally describe a single correct solution, but also leave a reasonable deductive pathway to that solution?

I think that's what boggles me most about this, the deductive pathway that's been created by the puzzle creator is a complete joy in its unfolding.

antfarm• 6 years ago

There is a pattern in the solution: Consecutive numbers are separated by one field and enumerated horizontally from the left to the right, wrapping around the edges, i.e. ..._4_3_2_1.

Every line of the solution has the same sequence of numbers, shifted by 4 places to the left relative to the line above it.

This makes me believe the construction is based on a clever observation and repetition of a pattern.

lonelappde• 6 years ago

Alternatively, count up by 4 left to right (aka your -1 every two squares), and count up by 3 top to bottom within a box.

macintux2• 6 years ago

I don’t have the math background to assess the accuracy of these replies, but they might explain it.

https://twitter.com/NikhilBukowski/status/126262285333933670...

chongli• 6 years ago

Sudoku at its heart is a graph colouring problem. When you add the new constraints, it changes the connectivity of the graph. This sudoku, with all of its extra constraints, becomes a highly connected graph which greatly reduces the number of possible valid puzzles. Throw in the fact that the grid is already symmetric about both axes of reflection and rotationally symmetric about the centre and that further constrains the set of valid puzzles.

I'm sure you could write a program to take all these constraints and generate a ton of puzzles and then scroll through them to find ones that look great. It also wouldn't be too difficult to sort them in ascending order of givens.

GreedCtrl2• 6 years ago

Speaking of great-looking puzzles, this youtube channel covered a visually stunning pi day sudoku some time ago. As you said, it uses extra constraints to reduce connectivity, but still, I find it amazing that the digits of pi can fit so well into a puzzle. (Pi begins at the top and moves clockwise.)

    +-----v-----+
    |   |431|   |
    |  8|   |4  |
    | 3 |   | 1 |
    |---+---+---|
    |2  |   |  5|
    |3  | 6 |  9|
    |9  |   |  2|
    |---+---+---|
    | 7 |   | 6 |
    |  9|   |5  |
    |   |853|   |
    +-----------+

https://www.youtube.com/watch?v=N41yZsxIsK8

swah• 6 years ago

How do know if a certain puzzle is impossible (ie malformed)?

matsemann6• 6 years ago

That is a "decision problem": Does this puzzle have a solution?

For Sudoku, that's easy to verify. That makes it an NP-problem. But for Sudoku, finding a solution is very difficult, so difficult that we say it's NP-Complete. So the only way to verify that a Sudoku can be solved, is really to try a bruteforce (potensially sped up with guesses/backtracking) and then find out if you cannot continue because of a broken constraint somewhere.

matsemann6• 6 years ago

For Sudoku, that's easy to verify.

I meant: For Sudoku, it's s easy to verify that a given solution is correct. (cannot edit)

Of course, being given the solution first in order to even try, can be a bit boring. For that, there exists "zero-knowledge proof" where one can reveal one knows an answer, without actually divulging it. Here is a writeup about someone doing that for Sudoku: https://manishearth.github.io/blog/2016/08/10/interactive-su...

billfruit2• 6 years ago

Any other puzzles with deep deductive reasoning where one can get better at through playing. One comes to mind: hexcells, any others?

matsemann6• 6 years ago

I also asked this question in another thread here, got some responses and included my tips: https://news.ycombinator.com/item?id=23245258

yesenadam3• 6 years ago

There's a whole world of chess composition/problems. You can even be a grandmaster chess composer or solver. Some composers are legendary in the chess world, e.g. Troitzky, Sam Loyd, Kubbel. Chess problems come in various kinds, and are a bit like cryptic crosswords - they seem impossible at first but there are customs, tricks, conventions which make them easier with experience. "The role of aesthetic evaluation in the appreciation of chess problems is very significant, and indeed most composers and solvers consider such compositions to be an art form."

https://en.wikipedia.org/wiki/Chess_problem

billfruit2• 6 years ago

What would be a good book to get into chess problems and the culture/aesthetics of them?

DonCopal• 6 years ago

https://www.chiark.greenend.org.uk/~sgtatham/puzzles/

nickysielicki2• 6 years ago

Here's a solver in python with z3: https://gist.github.com/sielicki/fd86d68733133f654128519b3c4...

(note, most of the code coming from here, I just slopped together the additional constraints, https://ericpony.github.io/z3py-tutorial/guide-examples.htm )

    $ time python3 game.py
    [[4, 8, 3, 7, 2, 6, 1, 5, 9],
     [7, 2, 6, 1, 5, 9, 4, 8, 3],
     [1, 5, 9, 4, 8, 3, 7, 2, 6],
     [8, 3, 7, 2, 6, 1, 5, 9, 4],
     [2, 6, 1, 5, 9, 4, 8, 3, 7],
     [5, 9, 4, 8, 3, 7, 2, 6, 1],
     [3, 7, 2, 6, 1, 5, 9, 4, 8],
     [6, 1, 5, 9, 4, 8, 3, 7, 2],
     [9, 4, 8, 3, 7, 2, 6, 1, 5]]
    python3 game.py  7.47s user 0.15s system 97% cpu 7.801 total

gabrielsroka• 6 years ago

Each row is a cycle [?] of 483 726 159. And even the cycles have a pattern: 665 665 66.

That is, you can rotate the first row by 6 to get the second row, then rotate again by 6, then by 5, etc.

The columns are almost as consistent, but not quite.

dreamer_soul• 6 years ago

I love how z3 code looks like magic! Seems like a good library to start getting the hang of

carapace4• 6 years ago

FWIW, "Boring Sudoku" a solver in Prolog w/ CLP(FD):

https://swish.swi-prolog.org/p/Boring%20Sudoku.swinb

- - - -

I don't mean this in a critical way, just an observation. To me the video was boring because watching a human do machine work is frustrating (to me). (As fast and as clever as that fellow is, he's still so slow compared to a computer.)

However, designing elegant constraint rules to encode the special constraints of this puzzle is also a puzzle, and that puzzle seems interesting to me. (Although not very because it's not that challenging.)

I have the same problem with most video games: after playing just a little while I get bored and want to reprogram the game itself instead of just playing it.

Do y'all feel me, or am I just a freak?

kryptn• 6 years ago

To me the video was boring because watching a human do machine work is frustrating (to me).

I wouldn't think Sudoku is machine work. Yes, a machine can solve it, but it's not intended to be machine work.

nickysielicki2• 6 years ago

That's cool, but that doesn't solve this puzzle. It's just a normal solver unless I'm missing something.

natrys• 6 years ago

I used Picat which provides a uniform API for many different flavour of solvers (e.g. smt module uses z3 underneath): https://gist.github.com/natrys/c19be79ac93578674540cdfa7a0df...

I get instantaneous answer with apparently zero backtrack with both SAT and SMT module. Though I don't know how reliable this statistics is.

glandium• 6 years ago

For some reason this video ended up in my Youtube recommendations last week, and I clicked on it because the thumbnail caught my attention. Didn't regret it, and I've watched a few others. Another that was pretty interesting in the development of techniques to approach it: https://youtu.be/Zk4qNEDXFSw

Edit: Ah no, the first I saw was actually https://youtu.be/hAyZ9K2EBF0 which has a diagonal rule, and a magic square in the middle.

swyx• 6 years ago

I was just thinking the other day how I've never seen a YouTube video at the top of HN. along comes this video to prove me wrong.

dathinab• 6 years ago

It did the follow up sodoku (a new miracle sodoku), which I think probably is a bit easier as it starts with 3,4 in a slightly more useful constellation.

I have to say while I'm not the biggest fan of normal sudokus the ones with extra rules are quite interesting.

And the cracking the cryptic channel has quite a bunch of such sudokus.

carlob• 6 years ago

At the beginning I was wondering whether 9 and 1 were to be considered consecutive. It's not stated anywhere, but it seems that the solution has this property.

billme• 6 years ago

Here’s link to the puzzle:

https://cracking-the-cryptic.web.app/sudoku/tjN9LtrrTL

About the guide to controlling the interface for the game:

https://cracking-the-cryptic.web.app/how-to-play

(Links are little odd, if you want to find them yourself, just click the YouTube, view the video description, it’s the top link.)

residualmind• 6 years ago

https://www.google.com/search?q=483726159

busterarm2• 6 years ago

I immediately saw what the full pattern was when he had half the 2s filled in and was wondering if he saw it and kept going through the solution for the purposes of the video, or didn't see it at all until the end.

That never ended up becoming clear and now I'm just left wondering.

SamBam• 6 years ago

Unsure what you mean by "the full pattern." Do you mean you could work out what the entire grid was, from just half the twos alone?

busterarm2• 6 years ago

The twos and the existing ones. I made a reasonable guess that proved to be correct.

All the twos had symmetry and can be plotted on the grid like a tile pattern...and every increasing number in a row is two positions to the left of the lower number. It was blatant at that point in the vid.

Right at around 12:14 and then confirmed by the 18 minute mark.

adenozine• 6 years ago

I get the feeling that he would be a very impressive programmer.

jcims• 6 years ago

This is clicking on an existential level for me.

Lex Fridman's podcasts in particular have been sort of forking in two directions lately, one on artificial intelligence, consciousness and just a somewhat muted wonder how the human mind operates and our present lack of understanding of how it comes together systematically to create our experience. The other is about physics and how the experimental and theoretical come together to try to give us a better understanding of the fabric of our universe.

For this video, in the former case it shows how plastic the mind can be. I'm probably about the same age as the guy in the video and honestly have been struggling with an experience of cognitive decline lately. To see how adaptive the brain is to not only develop grooves that accelerate analysis in the long form, but also adapt to new rules and constraints almost as quickly is really quite remarkable (and for me personally, encouraging).

His quick pattern analysis at the end uncovered the second case for me. This is obviously something we've seen in many other situations as well, but how a collection of 'particles' with multi-dimensional constraints can form order and even crystalline structure from almost nothing.

Very fun video to watch. Thanks for sharing.

tshanmu• 6 years ago

puzzles and progamming - two of the best ways to while away the time.

yesbabyyes• 6 years ago

This was great fun! They have a new miracle sudoku[0] up since a couple of days, as well. Seeing him color the potential twos (aside from two wrongly colored squares) and then piece by piece ruling them out almost looked like a game of life, with new patterns emerging.

[0] https://youtu.be/Tv-48b-KuxI

ropable• 6 years ago

This video was just fabulous to watch.

The Miracle Sudoku [video]

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