Sudoku as a Fairground Ride

[@cathybryant5119]

This is a puzzle that I absolutely would not have been able to solve a few months ago. But today I successfully worked my way through it without peeking at the video and I was thrilled to discover that I had followed Mark's solve path pretty closely. I didn't use the secret for the break in, but used the candidate values for the 29 and 16 cage with the same result, albeit much more slowly - it took me about 75 minutes to complete the puzzle. I have been working my way through all the GAS puzzles, which have given me many more tools for approaching a puzzle like this. Many thanks to Mark and Simon for all the amazing content and the patient teaching.

[@allendracabal0819]

Nice job!

[@srwapo]

Oh, it would have been so nice to have GAS puzzles available when I started working on these myself a couple of years ago, haha.

[@KestrelQ]

Thank you very much for the feature! I'm glad you enjoyed the puzzle and the break in :) You deduced the interaction between the Vs in box 9 and the 29 cage perfectly!

[@Paolo_De_Leva]

Thank you for confirming that the first part of the solving path was found as intended. Possibly Mark did not follow exactly your intended path later, but he brilliantly discovered and explained some alternative paths during his solve, as usual.

[@BrooksMoses]

That was an interesting interaction there, indeed. Nice setting!

[@emilywilliams3237]

This is a great puzzle - I saw that it seemed to be within my reach both by constraints and by the length of the video, and I did do it (with some help from time to time from your excellent solve, Mark). Loved the video, and the hint of Shakespeare (this sceptered isle) and that wonderful phrase you used, "eliminating a very impossible thing" - so fun. Thanks for all, Mark. (Though I have grown up calling it a Merry-Go-Round, only sometimes a carousel. I loved how the logic traveled around the grid, probably inspiring the puzzle's name. Congrats to Kestrel for a very nice puzzle.)

[@PaulWilkinsNZ]

19:35 "I could pencil-mark 2, 3, 4 and 5 into those cells, but it, it would be frowned on by people of this Parish." - I love it!

[@longwaytotipperary]

I’m in US and always called it a merry-go-round also. Nice puzzle - nice solve! Excited for all the good stuff coming up on the channel! You guys rock! ❤

[@allendracabal0819]

I just want to second that. "Merry-go-round" is standard in the US, too.

[@allendracabal0819]

(26:30) I still can't believe how fast Mark can spot naked singles, even though I've seen him do it many times. That's an incredible ability.

[@TheClawNinja]

So true...I find myself having to pause the video to see how all the other numbers get ruled out :)

[@gokuryu]

It's uncanny how he does that.

[@pierrenilsson6189]

@@gokuryu In a pub it is not hard at all but in a sudoku...

[@VeritasUnae]

Very cool breakin down the bottom there! Nicely solved Mark and well set Kestrel!

[@Ferrindel]

Wow. Blown away by how quickly everyone did this. I'm pretty good with Sudoku thanks to this channel - I just did the recent Phistomofel in less than 20 minutes for crying out loud - but this one has me completely stumped. I've got most of the bottom three boxes filled in more or less, and column 8 defined, but I have absolutely no clue how to proceed without EXTREME bifurcation, and nuts to that. So. I basically did this the hardest way possible. I used maths to determine possibilities for r7c1 and r9c6, and then after fully solving box 9, was able to figure r1c2c3 as adding up to 11. The thing I forgot to do was, doy, remember that those two cells MUST appear in box 7 column 1, obviously without the 5. So I had it all along, I just forgot the simplest deduction and instantly found the 29 pair.

[@ab22aq22]

Strange how I can be stuck for long time, go back to the video, wonder why Mark does not see ”the obvious” next step just to realise that it is exactly what I was blind to… repeat a few times and finaly finish in 54:43. I am full of admiration to Mark and Simon who does not need to watch someone else struggle, but finds the path sooner or later every day.

[@victorfinberg8595]

mostly sooner

[@davidh.4944]

43:55. I took my time and colored the grid. It was a rather nice solve that didn't hang up anywhere for long. Figuring out the break-in in the bottom rows was enjoyable. I realized that the 29 cage had to have a maximum of two low-value (1234) cells, which eliminated all the possible combos save one. That immediately placed the 9 in row 9 and 12 in R8C1. The rest of the puzzle followed from there.

[@lorenb6066]

Took me 4 attempts of always ending up with two of the same digit in a row. So went to check the video and as soon as Mark said "and what do we know about black dots?" after filling the 20 cage, I face-palmed. I'd been reading it as a white dot each time! But as you still get a 4 in r3c8 all the lovely back and forth still worked, so looked beautiful but ended up wrong. Finally did it correctly after all. Phew.

[@BrooksMoses]

Whoops! I've done that, though usually I read white dots as black-dot-constraints rather than the other way around.

[@benjaminrealy5661]

30:31. Loved how it went so slowly, until I could solve one particular cell, and then I was cooking. Great puzzle

[@mariellehoexum5487]

18.32 for me. Always feels good to solve a puzzle without help and then see Mark apply exactly the same strategies.

[@Coyotek4]

16:12 ... very enjoyable (and a welcome respite after today's 'Simon' video) Nice puzzle!

[@matthewjohnson6360]

Simon's was CRAZY.

[@ericpraline1302]

Pitched at a very jolly level of difficulty - it required thinking, but I never had to wait for very long before the next deduction arrived.

[@Rukimix]

I actually used a different break-in. Because of the interaction of the 29 cage with the V's you can't have more than 1 low digit on R9 (inside the 29 cage) or the V's would break, so you can have at most 2 low digits in the cage, one on R8C1 and another on R9 and the minimum sum of high digits for the reamaining cells inside the cage would be 26 (5+6+7+8), forcing a 1,2 pair on the 29 cage, which gives you the 9 on R9C6 and the 1,2 pair on R8C7 (because 1 or 2 will be forced into it by the 1,2 pair on the 29 cage).

[@BrooksMoses]

Interesting! That's equivalent to the logic of looking at how row 9 can sum to 45 and following from there, but a quite different perspective on it -- roughly speaking, you were removing digits from the {1,2,...9} set and looking at what the remainder sum to, rather than removing amounts from the sum and looking at the combinatorics of digits to make the remaining value.

[@kevinmartin7760]

17:43 I figured out some of the digits in box 9 differently. Your degree-of-freedom calculation getting the 9 in row 9 also required that the bottom row of box 9 total to 8 or 9 so R9C7 must be 3 or 4 and R8C7 must be 1 or 2 and the same 1 or 2 must be in the unassigned cells of the 29 cage and the opposite of the 1/2 in R8C1. The 5 in box 9 could not go on the white dot because it would need the 6 with it and the 16 cage would contain 7, 8, and two more digits, blowing it up, so the 5 had to be in R8C9 and the 7 on the whit dot. By elimination, the x in box 7 has to be a 1/9: * 3/7 is forbidden by the 7 on the white dot in box 9. * 2/8 would force a 1 into R8C1 and 2/6/7/8 into the unfilled boxes in the 29 cage; only the 6 and 7 can go in box 7, and the 6 along with the 8 of the 2/8 pair breaks the black dot in box 7. * 4/6 just plain breaks the black dot in box 7. The 1/9 on the x means R8C1 must be a 2, R8C7 a 1, R9C7 a 4, and a 2/3 pair in the bottom-right V. Solving the 20 cage forced the 7 and 6 in box 9, and the 8 in the 16 cage finished off the 1/2 in the cage. Phew, describing all that seems complicated!

[@Pablo360able]

62:01 for me! First time not having *any* false starts on a cryptic sudoku. I feel good about cottoning on to the strategy with the 40 cage right away and fully utilizing it as the puzzle went on, but I suspect I could have been more systematic with how I used the 20 cage; it would have helped me place the high numbers in box 9 sooner, and that was an important part of my breakthrough. EDIT: You’ve just started the puzzle and I realize the cage I was actually inefficient on was the 29 cage. Rather than just getting the 8/9 in r9c6 right away, I didn’t figure that out until after a whole mess of logic involving the two Vs in box 9 and exhausting different number combinations for the remainder of the cage. EDIT 2: I don’t even know anymore. I used the 20-cage to get the 9 rather than the other way around. How do I even compare that?

[@piarittersporn]

Wonderful puzzle, enjoyable and relaxing.

[@troy.s]

Coloring no longer needed... Mark: Whack it! Simon: Double down and color all the things anyways! Love coloring... just wish I could use it more effectively.

[@BrooksMoses]

30:02. That was fun, and I'm pleasantly surprised to find how close I was to the video time, too.

[@victorfinberg8595]

34 min. any day i need less than double Mark's time is a good day.

[@Raeker]

19:35 "I could pencilmark these cells but it would be frowned upon" me, who pencilmarked those cells precisely at this stage in the puzzle: 😧

[@inspiringsand123]

Rules: 04:47 Let's Get Cracking: 06:04 What about this video's Top Tier Simarkisms?! The Secret: 2x (07:02, 07:02) Knowledge Bomb: 1x (07:19) Three In the Corner: 1x (27:12) And how about this video's Simarkisms?! Ah: 8x (11:08, 12:54, 18:55, 21:34, 21:51, 22:48, 26:02, 27:59) Sorry: 4x (14:51, 18:36, 19:29, 24:40) Lovely: 4x (15:42, 16:13, 19:45, 20:26) Pencil Mark/mark: 3x (19:35, 20:29, 26:29) Brilliant: 2x (02:07, 03:46) By Sudoku: 2x (25:51, 27:50) Goodness: 1x (14:49) Bother: 1x (12:20) Clever: 1x (15:43) Beautiful: 1x (20:49) First Digit: 1x (09:34) Shouting: 1x (14:51) Approachable: 1x (04:10) Hang On: 1x (26:17) Irritating: 1x (27:37) In Fact: 1x (25:57) Progress: 1x (17:24) Most popular number(>9), digit and colour this video: Ten (9 mentions) One, Two (71 mentions) Black (12 mentions) Antithesis Battles: Low (8) - High (5) Even (2) - Odd (1) Black (12) - White (4) Row (30) - Column (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!

[@matthewjohnson6360]

I've puked on a merry-go-round, I also stumbed around for over 40 minutes before.

[@yellowtrumpetfish]

Today’s most shocking moment so far: Mark going to pencilmark the V’s and putting in color instead of digits 😱😱😱

[@srwapo]

43:11, I pencil marked a bunch, felt like I needed to, but then I failed to erase pencil marks when I figured out a number and spent so much time just scanning for obvious deductions.

[@joec2864]

After some rough solves on channel puzzles, I'm glad to have solved this one in 16:01--fun, not too challenging, and would have been even quicker had I not ignored the c8 black dot for minutes after getting one of its digits.

[@wanderlustwarrior]

18:15 for me, that was quite easy. I didn't try with the Simon video, so this makes me feel a little better about myself.

[@Gonzalo_Garcia_]

9:42 for me. Very nice puzzle!!

[@dalekloss4682]

Mark you need to visit more countries! Me laughing! They are commonly called Merry-Go-Rounds in America

[@Pablo360able]

Hm. A nasty thought just occurred to me: What if there were a puzzle that utilized the double-negative constraint? In other words, where it said “Not all dots, Xs and Vs are given”, but in order to solve the puzzle, you need to realize that means there *is* a dot, X, or V that *isn’t* given?

[@davidh.4944]

Technical feedback: The cage calculator isn't working properly for me in Firefox here. It displays all of the possible cell sums for the cage, and toggling the settings changes nothing.

[@cathybryant5119]

I have the same problem on Chrome on my Mac.

[@nickatty462]

Not just Firefox - I tried it on Chrome when I found the same thing. It's as though it's not reading the cage totals.

[@harriethogarth372]

I think it is now set up that you just scroll to cage total you want and see the options available

[@AzraelAG]

They're 100% called merry go rounds here in the US

[@ServantOfSatania]

38:23 I think the biggest challenge for me was figuring out when the coloring for 1234s I did has overstayed its welcome

[@irc_ninja6906]

62:41 amazing challange!

[@irc_ninja6906]

im watching now and this is so crazy because i used totally different strategy. wow.

[@Torauth]

Dots are the wrong way round on Dark Mode on the app, had me confused as it made bottom right box impossible

[@Sponsie1000]

yeah same,, l had to open it on my laptop just to be sure

[@lichterin143]

I found this one pretty hard-took me two attempts. But fun!

[@57thorns]

I spun around for 38 minutes before I stumbled out all dizzy.

[@57thorns]

I did use that you can't have more than two digits from 1234 in the 29 cage, or there would be five of them on row 9. This fixes what digits are in the 29 cage completely, as well as r9c6.

[@cathybryant5119]

@@57thorns I did the same. I'm not good with the mental arithmetic using the secret, so I tend to look at the candidate values and start to rule them out based on the situation.

[@Rach881101]

24:04 for me. Nice puzzle!

[@kwongshuchung]

33:14 for me Not a very tricky one, need some observations and calculation to break in

[@Ryan-ys1qc]

16:38 which I'm happy with

[@Pritchie45]

scepter'd isle

[@Chriib]

Nice puzzle. Actually the upper right box with no sum is not necessary to get a unique solution. The way I solved it didn't make any use of it.

[@DWestheim]

At 32 minutes, I almost managed to match the video length for my solve. Good enough by my standards, I say. :-P

[@clydew4423]

Please fix the white and black dots in dark mode.

[@josephbentley7780]

38:02 for me, i'm terrible with cages

[@hockeyhacker97]

12:44... Doesn't that then also mean that 29+(orange 8 or 9)+ 10 = 45+3 since the 2 not in the row are a 1/2 pair and so you can solve for the orange square and get 48=39+ unknown 8 or 9 subtract 39 from both and get the unknown as 9? there is zero degrees of freedom in the 2 digits not in the row being a 1/2 pair and so if we treat the blues as a 10 cage and the 29 cage, remove 3 from the 1/2 pair and that is 36 in the bottom plus the orange cell and so the orange cell is 9. As such had you done it the second way around you would not have come up with a 1/2 pair but rather a 1/2/3 because a 1/2 pair is 0 degrees of freedom, so you could not have actually done it the second way you where thinking of doing it since you would have added a 3 as well.

[@robertcousins2274]

28:20

[@yarnantics]

26:40 for me :)

[@LednacekZ]

11:55 for me. Nice one.

[@RADZIO895]

39:07 for me

[@PriffyViole]

Got it without the video!

[@leickrobinson5186]

The L-shaped cage in the upper right doesn’t appear to serve any purpose. The solve path doesn’t depend on it. 🤔

[@kyleoddson2367]

I used in; I tend to Goodliffe even more than Mark does, and it served me to remove an option from R3

[@josephbentley7780]

I used it to determine R3C5 was a 2

[@irc_ninja6906]

i use it to find 2 in box2

[@oldguydoesstuff120]

45 minutes. And no real help from Mark - started to watch a bit, then he started working in an area when I realized I had placed a digit in that area and failed to follow through on how that affected things. As is so often the case, just got to look at the obvious.

[@Pritchie45]

26 minutes

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

16:00 for me.

[@sidoldboy3442]

you can place 9 in row9 box 8, straight away.. 8+7+6+5=26 leaving 1.2 for the other two boxes in the cage, if it was 8 in row9, col6 then 9+7+6+5= 27 even 1,2 won't make 29... LOL come on Mark you can do better

[@theredstoneengineer6934]

19:14 for me