A Complete Fibonacci Fog!

[@nathanweston9681]

"Our chances of proving there's a 3 in the corner have substantially diminished," said Simon, immediately after proving there was definitely a 3 in the corner

[@tabris1135]

R5C9 after Simon said that: "Am I a joke to you?"

[@kathyjohnson2043]

But he did realize why he was wrong.

[@10bd1]

😂 classic

[@pianissimo7121]

I think he was thinking that the diagonals had to be unique digits and not fib series. Edit : i should have watched for a minute longer

[@JohnRandomness105]

@@pianissimo7121 You were correct. He was thinking that when he said that, for the moment.

[@philipa.7722]

Thank you so much for all the lovely comments. I met Simon earlier this year and have been excitedly watching his videos in my evening routine ever since. Before this, I never bothered with Sudoku. This was my first attempt at creating a puzzle. I'm thrilled that you, Simon, solved it in the video. Only the best to you all! Flipsen

[@puritan7473]

That was an excellent puzzle, what a great idea to use the Fibonacci sequences, and only a few simple pieces led to a solution, Fantastic, I loved it!

[@user-kt9vr1wj6y]

great break in !

[@Robertlavigne1]

This was a very fun puzzle for me! Doable for a determined but only moderately skilled solver, yet hard enough to make me feel clever for sorting it out! Lovely puzzle!

[@brenthoskisson6979]

It is a good thing Simon is in tune with you about what you mean by "Fibonacci Lines". The only sequence I have ever heard of starts with 0 and 1. Never 8 and 9 or 2 and 3. You might want to Google this and check for yourself.

[@Cid0484]

@@brenthoskisson6979 0,1 or 1,1 as start are both very common. Due to that fact I didn't understand the rules at all. Yet after watching Simon explain the rules and rereading them it is a lot clearer to me (still not intuitive at all)

[@Rubrickety]

After my own solve, I eagerly started watching the video to see what clever principle Simon used to avoid listing out all the possible sequences and eliminating those that broke or clashed, since he never uses scratch paper. 🤣

[@avisian8063]

That has to be one of my absolute favourite sudoku. The break in was really cool, and then the sudoku that followed was still fun and rewarding. Often with these kinds of break ins the puzzle kinda solves itself after, but this still had some teeth all the way to the end imo

[@AlRoderick]

Fun fact, the Fibonacci numbers are an easy way to do a quick estimate in converting between miles and kilometers because the conversion factor is really close to the golden ratio, which is what adjacent fibonacci numbers approach as they get bigger. So if you see a figure quoted in miles and it's a Fibonacci number the next one will be roughly the equivalent in kilometers

[@57thorns]

Wow, interesting fact but not very practical. 🙂

[@AlRoderick]

@@57thorns it's more practical than you think. You only really need about two digits of precision, so you can easily generate the sequence and you only need to get about as far as 5, 8, 13, 21, 34 and that gives you basically all the ratios you need If you also scale them by tens or hundreds. 800 km, about 500 miles. High speed train travels at 350 KPH, that's a little more than 210 mph.

[@kathyjohnson2043]

I think this is something I will actually use (and, yes, I DO use Algebra in 'real' life too)

[@charltonrodda]

It's close, but it's barely closer than 8/5. In fact, the mi/km ratio is almost exactly in the middle between 8/5 and the golden ratio - it's 0.000327 from the midpoint.

[@DarklordZagarna]

I've always found this factoid one of the more delightfully weird coincidences in the physical world. At least, I THINK it's a coincidence... [cue x-files music]

[@jodinha4225]

Never thought id be a Sudoku fan but Simon's commentaries make the game really interesting. He's very good at making the underlying logic behind these puzzles seem fascinating instead of frustrating.

[@longwaytotipperary]

Agree!

[@Hakucho64]

Just be prepared for frustration when he ignores low-hanging fruit and starts wandering off on tangents about odd/even digits and whether there’s any chance of 3s in corners. 😅

[@KeiFlox]

No surprise at all that Flipsen is a math teacher, wow!! What a rule set.

[@jodinha4225]

Whenever I see a ruleset like this I know its either gonna be beatiful or completely nightmarish. Theres never any inbetween lmao

[@Jodawo]

I remember a more fearful puzzle in Simon's past. It was called Chaotic Wrogn. When he opened it live at Mark's request, one of the first things he said was "Nope, nope, nope I'm not going to do this." I think before that he said "I've seen this one" or something along those lines. It's definitely one of his best video moments for CTC or at the least in the top 10 in my opinion.

[@jaimyhelders8009]

I usually just watch these videos in awe, not knowing if I will ever solve one of these puzzles. I had a go at this one because of the interesting ruleset! To my surprise it actually went really well; 43:41 for me. What a fantastic puzzle, and great debut for Flipsen.

[@GuKingGu]

“Actually, that’s distressing, because I could have either 8s or 3s on the middle diagonal” Having got stuck and had to watch the video to see how Simon solves this, it’s good to see that at least we’re following the same thought process!

[@kindlin]

I was completely stumped by the wording of the rules. "Consecutive digits? But only 1 and 2 are consecutive...." and I still didn't understand what Simon was doing until he put in 3-4 in his example row 3 and I said, "But that's not in the sequence! OOOHHHH _Any_ consecutive digits!" and I just skimmed the rest of video real quick. Interesting idea.

[@fawful9992]

One thing I noticed is that all sequences that start with an odd number have an 8 in the middle while all sequences that start with an even number have a 3 in the middle.

[@jvanyai]

Yes, this is forced. An odd number can be written as 2k+1, for any integer k. Therefore the first 5 terms of a Fibonacci sequence starting with an odd number are: 2k+1 2k+2 4K+3 6k+5 10k+8 10k+8 modulo 10 = 8 for any integer k, and therefore the middle digit is 8 for any odd starting digit. The same logic holds for an even digit at the start, mutatis mutandis.

[@inspiringsand123]

Rules: 04:52 Let's Get Cracking: 09:34 Simon's time: 27m40s Puzzle Solved: 37:14 What about this video's Top Tier Simarkisms?! Bobbins: 5x (13:59, 14:09, 14:15, 14:15, 17:41) Three In the Corner: 3x (18:58, 21:31) Knowledge Bomb: 1x (01:45) Diddly Squat: 1x (09:39) And how about this video's Simarkisms?! Ah: 23x (11:28, 11:39, 11:39, 12:03, 12:48, 13:56, 14:12, 14:25, 14:52, 15:55, 16:22, 22:28, 22:34, 23:15, 23:23, 25:34, 25:34, 26:06, 30:31, 31:16, 31:58, 32:50, 36:07) Hang On: 10x (12:25, 13:59, 21:08, 21:38, 21:52, 23:23, 24:34, 24:34, 34:49) Sorry: 9x (03:24, 03:29, 03:40, 03:56, 04:05, 04:05, 16:16, 21:28, 24:42) By Sudoku: 7x (23:11, 25:04, 25:52, 26:46, 29:14, 29:56, 33:38) What on Earth: 4x (01:00, 14:25, 14:33, 28:53) Beautiful: 4x (18:44, 18:46, 22:56, 25:44) Cake!: 4x (03:38, 04:23, 04:38, 04:45) Naked Single: 3x (25:38, 32:08, 35:51) Goodness: 2x (15:50, 35:46) Clever: 2x (15:59, 15:59) Fascinating: 2x (00:58, 01:22) First Digit: 2x (05:17, 10:37) Gorgeous: 2x (22:37, 37:11) In Fact: 2x (27:28, 29:30) Thingy Thing: 2x (27:11, 27:14) Pencil Mark/mark: 2x (31:20, 35:06) Apologies: 1x (02:57) Missing Something: 1x (14:46) Naughty: 1x (34:49) In the Spotlight: 1x (21:35) Stuck: 1x (33:08) Horrible Feeling: 1x (18:50) Epiphany: 1x (12:07) Surely: 1x (32:16) Whoopsie: 1x (20:30) Losing my Army: 1x (16:16) That should be a Something: 1x (37:01) Unique: 1x (12:18) Most popular number(>9), digit and colour this video: Ten (19 mentions) One (84 mentions) Black (9 mentions) Antithesis Battles: Odd (3) - Even (3) Black (9) - White (3) Column (10) - Row (9) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!

[@mcpecommander5327]

One isn’t greater than 9

[@inspiringsand123]

@@mcpecommander5327 "Ten" is the number greater than 9 and "One" is the most popular digit

[@KestrelQ]

Very nice break in, well found by Flipsen! The rest of the puzzle just falls into place beautifully after that

[@sylvanshroom]

This is the first one I've solved on my own besides the video- what a satisfying puzzle! So many mind blowing moments in the solve!

[@jesperwillems_]

Congrats! I remember my first solo-solve like two years ago after so long of watching the videos thinking “no way i could ever do this” - watch out, solving them is addictive! And gets remarkably easier with every new solve you do!

[@anaayoung9142]

Very interesting sudoku. I did not understand at first, but after you got the sequence I think that was more easier than I expected! Nice one as always! 🧡

[@OlafDoschke]

I once confused a waiter whether I can get Fibonacci instead of Fettucine. This sudoku was as amusing.

[@quothacreations3465]

roughly a third of my solve time was devoted to figuring out the Fibonacci break-in; after that it was smooth sailing. well done, Flipsen--a beautiful puzzle

[@JohnRandomness105]

I couldn't find anything any simpler than decimating the possible Fibonacci sequences until only two were left with 3 in the center. I assume the creator intended this.

[@trudain]

Had to watch your explanation of the rules before the penny dropped. Then completed in 23 mins. Thanks!

[@goldcakes]

"It's bad for our prospects of 3 in the corner which have now disintegrated" was hilarious, though one prospect had died you managed to save the other. I managed to finish it alone in 01:28:06 Interestingly, if Simon kept the failed sequences at the beginning as he filled the potential Fibonacci lines, the grid would show interesting patterns in each column. Each column had the same difference between the digits(counting 0s) going down the rows, e.g. column 1 and 2 the difference was 1, while C3 was 2 and C5 was 5. These differences were in this order from C1 to C9: 1, 1, 2, 3, 5, 8, 3(13), 1(21), 4(34)

[@ericsjoberg8167]

This was easier than I first thought. Great puzzle, fun mechanic! Thanks to the setter!

[@wanderlustwarrior]

I couldn't do this one on my own, because while I correctly started the proper break in, I misunderstood the rules to believe you had to double the first digit, which breaks it.

[@DarklordZagarna]

Well, yeah, doubling up a number is going to pose problems for a sudoku... Maybe try creating a Fibonacci Filomeno?

[@victorcarrasco4248]

No shame in that! I struggled the same way!

[@MaierFlorian]

"... the technical term 'thingything' used for row 5 here" 😍😂 made my day

[@longwaytotipperary]

I use that technical term quite a bit! 🤪

[@davidrattner9]

He uses that technical term regularly now.

[@davidrattner9]

​@@longwaytotipperarythingy thing is such a wonderful phrase to use around the office or in everyday life 😃❤️

[@longwaytotipperary]

@@davidrattner9 absolutely! 😁

[@klausku3285]

What a brilliant idea. And nicely executed. Loved it.

[@chocolateboy300]

I finished in 66 minutes. I got confused twice during this puzzle. First, I thought that it followed the classic Fibonacci sequence, starting with 1 and that it could be anywhere on that sequence, completely forgetting that other sequences exist. The second was the rule that said the first digit was the smaller one, which I thought was obvious cause Fibonacci sequences are always smaller in the front. I didn't realize that this was referring to the consecutive digits. That would have saved me half my time. Otherwise, that was very fun to figure out. I had to write it down, cause I couldn't remember it all in my head. Placing all the digits for one diagonal all at once was very satisfying. Great Puzzle!

[@Kirbyfan87827]

Finished in 27:33 with some help from the video; I wrote down all the possible sequences on my own, but I needed Simon to point out which ones wouldn't work so I could get the first central digit in and start clearing fog.

[@marie-juhanna1281]

I solved it in about 37min (forgot the exact figure). Was quicker on the Fibonacci breakin, because I understood immediately that the middle digit must be the same, so I also listed every possibility and saw that a few wouldn't because I wrote them as a cross, as they would appear in the sudoku grid. This way it was easy to see, that the 4 and 6 collided in some of the combinations. Got the two diagonals filled in in about 10min, but afterwards got a bit stuck at the point, where the little arrow in box 8 would help. Some parts I did completely different to Simon, very cool to see another way of doing it. But to conclude, this is a really cool puzzle, loved the Fibonacci diagonals.

[@ziggyziggyziggy]

Exactly the same here. Immediately stopped the video after that and solved in 34:24.

[@JPRobinso]

Flippin 'eck - took me 95:04 and I had to write out all the Fibonnacti options, and thought I'd broken it till I watched the start and realised I could make some other options not work, then it was still quite a struggle to work my way through. Nice puzzle.

[@longwaytotipperary]

Really enjoyed this! Listened while stuck in traffic, then watched when I got home!! 😄

[@davidrattner9]

Great way to deal with the fun times of rush hour traffic. 😁

[@longwaytotipperary]

@@davidrattner9 it does lessen the frustration level!! 🤪❤️

[@agoristtaxadvice]

An excellent puzzle. Woul dhave NEVER figured out just going through the sequences looking for overlap on my own. Brilliant Simon.

[@PathOfShrines]

Neat idea. I wrote out the 8 lines and looked for conflicts; it wasn't until I sketched out a couple of trial grids that I realized that conflicts could come from opposite ends. That immediately broke the puzzle wide open, and from there it was really a mop-up. 27:18. I just realized that I assumed that the lines started from the left, which isn't stated in the rules. It doesn't actually matter in the end, though, since the conflict rules work the same either way, and the configuration is easily locked in by what you can see from r5c5. Still, I would suggest adding something like "lines can start from either end" explicitly to the rules.

[@MBSPUHR842]

Didn't understand the rules at all so I watched the first few minutes of the video as Simon began writing out the possible lines. Took me 43 minutes after that including calculating all the possibilities just like Simon did (it's always nice to see you did it his way, even if he isn't sure that it was the fastest or most mathematical way). My conclusion is that a piece of paper would have been better than the way Simon and I did it using the center digits on the screen. But it was a fun puzzle, especially seeing practically the whole grid clear except for the edges of the even boxes.

[@jonhansen9622]

Looks like quite the challenge, but I Do love these fog puzzles!

[@chris5619]

I love the fog of war puzzles as well. It's also nice that you always know where to start. Even in this one, we obviously had to figure out the only two sequences that could go together, so you just have to start doing that.

[@imogenoliver]

Such a cool puzzle, great setting Flipsen 😀.

[@piarittersporn]

The beginning was mind bending and without help (r5c5) I would have been lost..... after this help I could solve it on my own. Great puzzle.

[@hewholimpsmartin]

That was a phenomenal debut Excellent solve

[@DoubleJumper]

The rules left me really confused as to where the line actually starts from. I assumed top left to bottom right and bottom left to top right, and then making sure it starts by whichever end has the smaller digit ("The first digit in a Fibonacci line is always the smaller one"), but that didn't seem to match.

[@sonalita_]

It's corner to corner but the starting corners have to be determined by the solver... so you have to think of what the central square could possibly be....

[@julius9055]

Yh and I was confused because I thought the 9 digit sequence had to be from a part of the fibonacci sequence which started with two consecutive digits rather than what it actually was (the fibonacci result from starting with any two consecutive digits 1-9). Confusing ruleset imo.

[@easternblot]

@@julius9055That’s how I interpreted the rules as well (that each line had to start with two consecutive numbers but both from the same long sequence)

[@Coldheart322]

Thanks Simon, I had bit a bit of a brik wall in working out what to look at next. So I decided to watch your solve a bit. As you were looking at the potential fibonacci lines, you had an Ah ha! moment... and I paused the video before watching what you had spotted, and went off and got past the block. I think it's because you talked about the problem with using the same starting point twice, and how the 1st digit would block the second line, that my brain finally took the next logical deduction without seeing what you had actually seen.

[@QuarkTwain]

Friendly suggestion, when writing candidate digits in the fog, it's much easier to read if you highlight them in yellow 🍋 or orange 🍊

[@pspl80]

I just love your "ahhh"'s when you miss draw a line (16:21) 😂😂😂😂😂

[@pspl80]

It's sooooo funny!!!

[@craigjackson5210]

I confess I have never heard the “3 in the corner” song except for on these videos. So imagine my joy when I heard it in the hardware store today! Ha It was a revelation!

[@daniellucas5522]

Art. Absolute art. Just so wonderful to solve.

[@eddieharwood7788]

I loved that. I got started really quickly, and then once I'd used all the clues, less the 48 black dot which was still fogbound, I was desperately slow on the sudoku - kept failing to spot naked singles or pairs.

[@karsaanita]

I was doing number theory in my head at 7 am today because I failed to see that the two starting digits of these Fibonacci series need to be CONSECUTIVE. This is how I know I'm overtired; when I forget half the rules of a sudoku puzzle 😅

[@CrimsonSlug]

Getting that first digit was a very fun puzzle on its own.

[@Gonzalo_Garcia_]

18:39 for me. It took me ages just to understand the ruleset.

[@Raven-Creations]

@ 11:34 - "Aargh! Why can't I type?" - We've all been wondering that for ages. It's an interesting discovery that there can only be those two sequences on the diagonals. It would be interesting to know whether this would have been too easy without the fog. I don't think it contributed much, other than focussing the attention on the sequences at the start.

[@emilywilliams3237]

This was interesting. I paused the video after you explained the rules and made an aide memoire of the different sequences, eliminating all but the same ones that you did. Then I plotted them, figured out which ones had to be the ones - and then watched you solve it. Thanks for featuring this mathy of a puzzle, Simon. Enjoyable.

[@longwaytotipperary]

“Mathy” I like that!! 😄

[@davidrattner9]

Always enjoy your vernacular. 😀

[@Sam_on_YouTube]

Solved in 29:38. I like the interplay of a relatively simple rule with a completely fogged board that leads to a break-in. It was pretty clear right away the only cell you could possibly break into is the middle, as the blank board is symmetric. So I just listed the possibilities and only 1 combination worked.

[@srwapo]

22:45, found this one a bit tough at parts, which I find surprising given my final time. The break in took a bit of trial and error for me (I wrote out all 8 options on a piece of paper and figured the middle cell had to be a 3 or 8, but didn't see a logical way of going from there, ended up trying different possibilities and seeing how they broke on the grid itself). Was stuck a few more times, like on the arrow in Box 8.

[@mev135]

i was (and am) confused about the fibonacci rule. I thought there is only 1 fibonacci serie. So i started building it,modulo 10, until i came into a loop. On that loop you don't find all series that Simon used.

[@stevewithaq]

18:56 Simon: It's bad for our prospects of 3 in a corner. The grid: showing the correct Fibonacci sequences, one of which will force a 3 in a corner.

[@j4v4x]

Did I hear double bobbins? (gasp) Well done, Simon!! Beautiful break-in to the puzzle, I'm just sorry you had to do some sudoku at the end. :D 😂😂

[@longwaytotipperary]

There was even a “bobbins McBobbins face” 😁

[@michaellautermilch9185]

Attempted this puzzle for myself before watching. I have a perfect mathematical proof that the central digit must be 5. Only problem is I'm wrong!

[@michaellautermilch9185]

Oh I see what I did wrong after watching the video. I assumed the diagonals had to come from the actual Fibonacci sequence instead of being any 2 consecutive numbers. Certain consecutive numbers will never exist in the real Fibonacci sequence mod 10 (i.e. 3, 4)

[@KANPAI666OPPAI]

22:12 for me! Pretty interesting concept and it's crossed my mind on a couple of occasions how one would make a Fibonacci ruleset and this was a clever realization of such an implementation. My only complain was that the initial break-in just felt like a bit too trial-and-error to me with having to run through each possible permutation to narrow down to the pair of sequences that ostensibly fit.

[@sanabas1]

I wonder if that superfluous white dot in box 4 was placed in the puzzle just for people like Simon who don't like to do sudoku? Much easier to spot the logic @27:20 than it is to use basic sudoku to look at 89 in r4 & c2. I did the same thing, looked for restrictions on the given dot in preference to spotting sudoku. :D edit - I should have watched the next bit of video.

[@timbeaton5045]

As usual, Simon goes along a logical path, then jumps away to look at something else without continuing the logic to its end. If he had started filling in the line with a 9 he could have instantly ruled it out (the next digit would be a 10!) . Thus leaving the only two lines with the same middle digit as being the only candidates for the diagonals.

[@RichSmith77]

Not sure if I've misunderstood, but there's nothing in the rules that says the Fibonacci sequences have to start on the left on the diagonals. When he's looking at a sequence "starting with a 9" he's just looking at the reversed sequence that started 235 at the other end.

[@bertbergers9171]

30:24 is a pretty time to me. Thank you for the video Simon and thank you Flipsen for a nice puzzle!

[@DarklordZagarna]

31:52 A rare linguistic error from Simon, usually the master of wordplay, here (though the error itself is incredibly common). There's no such thing as "honing in on" something. You can "HOME in on" something-- think a homing missile-- but "hone" means to sharpen (so one might say that watching Cracking the Cryptic helps hone your sudoku skills), and of course to say "sharpen in on" something is a nonsense.

[@heatherfyffe3618]

Took me 11 minutes for the break-in, then 20 minutes for the rest, which mostly flowed very easily. I got as far as figuring out 3/8 in the middle (and that the 2 diagonals had to be different) but was stuck for quite awhile trying to figure out which pair of digit sets could be used. I watched the video just far enough to see that he was doing the same thing, writing out the sequences to see which ones do or don't exist. Knowing that he was on the same thought track as me, I figured I'd go back and keep thinking, paused, went back, and within seconds I saw it. :)

[@MyriamTT]

This was an amazing start for a puzzle !!!!

[@zelba20]

Loved watching the solve, well done!

[@BaldorfBreakdowns]

I love that the ways Simon deduced which sequences didn't work, were completely different from how I did it.

[@dustinkeier9176]

How did you do it?

[@sonalita_]

I used excel )

[@BaldorfBreakdowns]

@@dustinkeier9176 I just looked at the first and last digits, like how he deduced it can't be the same sequence. Which in retrospect doesn't actually discount the combo with 6's. Every now and then I miss a combination like that, gotten me in trouble many a time...

[@RichSmith77]

​@@BaldorfBreakdownsNor the pair that he first ruled out, due to clashing 4s.

[@BaldorfBreakdowns]

Oh yeah... I'm dumb lol I thought the 3's clashed for some reason

[@roberlucas]

Greetings from Cadiz everyone!

[@Nitrammful]

I was there this summer, what a beautiful city !

[@RichSmith77]

@24:55 Would it be churlish of me to point out that 3½, 4½, 5½ are not half of 5,7,9? 🙂

[@Kelters]

Fun puzzle, The break-in requires a bit of Elementary Math! Took me a while. After that it is a nicely logical puzzle to complete. I see about 6200 solves now 24 hrs after the release of this Simon's solve nº1. Great stuff!

[@soulseek2]

i really liked the break in part and the logic that followed on the left but towards the end it really showed me how terribly awful i am at solving (classic) sudokus

[@jordicochegrus657]

Quite proud to say I managed to accomplish only using a clue once today! I really should have known that pill had to have its 1 on the leftmost digit much earlier, but really happy with this puzzle and I had loads of fun solving it

[@ProBadSing]

Super cool break in!

[@HP4L16]

Classic Simon: misses the obvious x-wing of 8s that would easily resolve the puzzle then proceeds to find a naked single.

[@justinsmith2363]

Simon pointed out that he could have placed an 89 pair on the white dot using only Sudoku. Surely that makes the white dot clue spurious?

[@philipa.7722]

You‘re right! Didnt discovered that

[@gotbread2]

Really nice puzzle. I tried all permutations of fibonacci sequences, but i missed the "first 2 digits consecutive" clue. Once i re-read that part, i managed the break-in and came quite far, but i got stuck on the 168 triplet on the end.

[@johannygren116]

A very nice puzzle. I think my solve was about the same as yours except finding the 8 in box 6 due to an x-wing of 8s in box 3 and 9

[@chris5619]

This is the sort of puzzle that makes me think maybe I could actually come up with an idea to set one myself. Some of the puzzles on this channel just have me thinking it's insane anyone could come up with it. That's not to take away at all from this setting, it's great, but maybe I'll actually try to put something together sometime.

[@zmitter4844]

You should! I've only set a few puzzles myself but it's always a good time!

[@Nxluda]

I got stuck breaking in. I treated the term "fibonacci line" as any series of numbers that's generated when you take the sum of the previous two number (a,b) and find the modulo ten of it. I expanded every series of numbers. First I ignored every (a,b) pair where a was larger than b. I then did the fibonacci sequence backwards from pairs that add up to 10. Ignoring any (a,b) pair where a was smaller. Then i ignored every (a,b) pair that did not have another (a,b) pair whom to share a middle digit with. After that, i eliminated pairs of pairs that broke Sudoku rules. Mainly two of the same digits sharing a row or column, or two of the same digits in the middle box. After all that I got 3 sequence pairs. 1,3,4,7,1,8,9,7,6 and 3,5,8,3,1,4,5,9,4 2,3,5,8,3,1,4,5,9 and 8,9,7,6,3,9,2,1,3 4,7,1,8,9,7,6,3,9 and 6,9,5,4,9,3,2,5,7 I probably misunderstood the ruleset, but when I read the smaller one I read a is smaller than b, not a is smaller than be by one.

[@steve470]

"9-cell diagonals are Fibonacci lines (in modulo 10) starting with two consecutive digits."

[@ExodaCrown]

That was an awesome break in, ! wasn't sure how you were suppose to start the puzzle. I thought you tried a number in r1c1 then go from there. Which was totally wrong, but helped me understand the Fibonacci rule. So outside of cheating on the first digit, I found the puzzle to be fun. Even if I understood the rules better I don't think I would have written out the possibilities to check for overlap.

[@LednacekZ]

17:34 today. 10 of them was translating the rules to human speach.

[@turun_ambartanen]

23:41, beautiful puzzle. Took me a bit to understand the rules, but it was beautiful!

[@titusadduxas]

30:55 - Having spent ages looking at all the mod 10 sequences I re-read the rules!!! It was pretty straightforward after that!

[@Edos512]

i needed more time than i want to admit to find the 2 diagonal sequences

[@MattYDdraig]

22:09 A clever idea, but i got very confused at the start by reading the meaning of consecutive digits as consecutive withingntje Fibonacci sequence and proved the niddle digit could only be a 5! And then fog didn't clear. I wasted about 10 minutes before realising it meant consecutive in the counting sense which gave a very different result and everything feel into place. A nice idea if my comprehension hadn't gotten in the way.

[@thumper8684]

My dyslexic eyes just did not see the word "consecutive" in the first sentence. Maybe it was because I thought I knew what Fibonnacci lines must be, because I know what a Fibonnacci sequence is.

[@Hakucho64]

Got stuck because the programmer in me insisted that all Fibonacci sequences start with 1,1,2,etc. Once Simon showed how to consider other options and how they might interact, I was away to the races.

[@GianniBergandi]

28:29, very cool puzzle !

[@EmonEconomist]

29:22. I messed up with the white dot in R9 initially and treated it as a black dot, which got me horribly twisted and I had to backtrack. But it went a lot better after that.

[@user-sw8xz7re9z]

Loved this! The rules confused me, and I don’t think I could have broken in. However, one thing I think I noticed watching was that Simon had a lucky mistake on the 7 in box 5. He pencil marked 7s in r5c4/6, that placed the 7 in box 4. However, unless I missed something he then placed the 7 in r5c4, without any apparent reason (at least to me).

[@RichSmith77]

He was using the centre pencilmarks (57) rather than the corner pencilmarks, to place the 7 in r5c4. It was an interesting feedback. The corner pencilmarks in box 5 initially resolved the 57 pair in box 4, and then the 5 in box 4 resolved r5c4 in box 5.

[@barefootalien]

This needs a bit of a rules clarification IMO. At first I thought it meant that the diagonals had to be selected from *the* Fibonacci Sequence modulo 10, i.e. from the 60 digits of its Pisano period, selected from sequences that start with an ascending consecutive pair and avoid 0, of which there are three. Only once I'd ruled out all three did I even _consider_ doing more general sequences of that form starting with 12, 23, 34, 45, etc.

[@Antiknight]

00:13:06 for me! Nice fog puzzle but the rules are somewhat confusing.

[@ryaneakins7269]

So where is the first cell of a diagonal? I assumed they were going left-to-right, but Simon starts top-to-bottom. Or is that part of what we're trying to discover?

[@KANPAI666OPPAI]

In this case, it's the part to discover - there are only two 9 cell diagonals, and they have a common cell between them. Step 1 is finding which sequences match in such a way, and then step 2 is figuring out the direction of those sequences, which if you do a good enough job mapping out the possible values along the diagonals, it'll work out really nicely.

[@jasono8783]

35:20 for me! wild puzzle

[@WimmekeVL]

Woot, solved my first one in 01:19:15 Great content. Highly recommended. I was first introduced to these kind of puzzles by a former colleague named Guy Van Hooveld. I'm not sure if he's still involved in the world of Sudoku. Does that name ring a bell by any chance ?

[@TrabberShir]

1:58 ... well this is the top comment so I will just upvote that and leave this to feed your engagement metric.

[@grantfraser5430]

I went absolutely nuts figuring out not only all 36 possible sequences but extended to include all 72 two number sequences in an infinite space. I found two cyclical possibilities and four terminating sequences. I found 8 possible pairs of sequences that satisfied all conditions but one and decided it was impossible to determine the center square except by guessing. Puzzle is broken unless I missed a rule. I missed the word consecutive. Now I understand why Simon didn't consider "all" the possible sequences. Why do i ever doubt Simon?!

[@SatanicNerfd]

Want to get started on it and I don't want to spoil myself but the rules seem unclear to me. When it says the diagonals are Fibonacci lines, can that mean both from bottom-left to top-right and vice versa?

[@RichSmith77]

Yes. The puzzle allows you to deduce the direction, with any direction along the diagonal being a possibility.

[@benanderson4118]

I listed all possible sequences on a spreadsheet and then figured out which two could work together.

[@matttabak2486]

Yay my birthday sudoku!

[@chris5619]

Is it cheating to use excel to easily layout all possible diagonals and then scanning them to see where the overlapping digits would rule out options? I started making an aide mémoire as Simon did, but quickly decided to pop over to excel.

[@MisterM2402]

I normally break out Excel for these types of puzzles. But now I'm left with 10 possible pairs of lines and no idea how to narrow them down further. There has to be some clever logical way to figure it out without writing every possibility down.

[@chris5619]

@@MisterM2402 I won't completely spoil anything, but if you want to figure it out on your own, don't keep reading perhaps. In the end Simon basically did the same thing, he just did it all on the grid on screen. When I put them all in excel, you have 8 total options (can't start with 9). Three had a 0 in the sequence, so those came out. Then the middle had to be 3 or 8, which was the first thing I was looking for. I decided to see if I could eliminate the 3 first, and couldn't (so figured it had to be correct, but made sure first). Each of the two possible pairs of sequences with 8 in the middle would have conflicts in the 2nd/2nd to last position, or in box 5. Again, it's all the same thing Simon worked out on screen, I just did it all looking at a spreadsheet.

[@MisterM2402]

@@chris5619 Managed to finish the puzzle on my own. Here's where I went wrong: I missed the word "consecutive" in the rules! I thought you could start with 1-2, 1-3, 1-4, etc. not just 1-2, 2-3, 3-4, etc. So I had a LOT of possibilities to narrow down. The rest of my thinking was on the right lines, I just missed a crucial word.

[@LeaAddams]

I mean, only if it's cheating that I did exactly this using the sudoku grid itself to do the same thing? Although tbh, given that doing sudoku is purely for one's own enjoyment, I think anything that doesn't make one feel like one is cheating oneself, almost-by-definition isn't cheating. 🤷‍♀

[@stevieinselby]

Nothing stopping you using Excel, but I'd be surprised if it was quicker or easier to programme that in than just to get a pencil and a bit of paper and write them out by hand...

[@adrianhead6272]

Took a few minutes to actually decipher the meaning of Fibonacci line (as opposed to "the" Fibonacci sequence)... but then taking 11m54s to complete (as it quickly falls into line).

[@57thorns]

22 minutes took it for me, once you figure out the sequences you have a lot of digits.

[@NelielSugiura]

"The reminder you get..." the typo is distracting! :(

[@kusanagi1394]

On minute 34:25 you identified a 168 tripple column 7 and pt the 7 in row 9. Why was it certain? Couldn't be the 7 in row 6 at this point of solving? Edit: Nevermind, you said it in the next sentence :D