An Iconic Optical Illusion, in Sudoku Form!

Here's where you can play The Escherian Stairwell by Chris Savvides: app.crackingthecryptic.com/99...
Normal sudoku rules apply. Digits along an arrow must sum to the circled cell. In the two 'staircases' (denoted by dashed squares) each digit is followed by a larger digit in a clockwise direction, unless the digit is a 9, which is always followed by a 1.
▶ OUR PATREON PAGE - JOIN THE COMMUNITY, SUPPORT US AND TRY OUR PUZZLE HUNTS◀
/ crackingthecryptic
This month’s Patreon reward is a fascinating collection of puzzles based on snake eggs by the great Philipp Blume. You don’t already have to be an expert on the genre to enjoy this one, as the earlier puzzles will help you build toward success in the later ones. Join us for $2/month for the monthly reward, $3/month or higher to have access to solution videos. All members have access to a Patreon-only discord channel to discuss the puzzles and get help! (Lots of other great content on Patreon includes past rewards, cryptic crossword solves, more!) We really appreciate your support!
Recently released on our Patreon site (completely free) is a new, beautiful pack of Fog of War puzzles by Sandra & Nala called ‘Joyful Moments.’ Go to our Patreon link above to access the puzzles.
▶ Find our merchandise here: ◀
cracking-the-cryptic.creator-...
▶ Cracking the Cryptic BOOKS available here ◀
Did you miss the Kickstarters for our books and e-book? You can now order them here: coffeebean.games/product-cate... Cracking the Cryptic’s Greatest Hits Vol. 1 and Vol 2, as well as the e-book editions of Fog of War (regular and deluxe editions), are all available!
▶ Cracking the Cryptic App ◀
Our main app (which is itself completely free) contains packs featuring Domino, Lines, and GAS puzzles, with a few special free sets as well! All the puzzles are hand-crafted by us and some of the best constructors in the world, with hints by Simon and Mark.
AppStore apps.apple.com/us/app/crackin...
Steam: store.steampowered.com/app/20...
Android: play.google.com/store/apps/de...
▶ ALL OUR OTHER APPS ◀
All our apps contain handmade sudoku puzzles by ourselves and many of the best constructors in the world, tested and hinted by Simon and Mark. Links are ALL here: crackingthecryptic.com/#apps or search for Cracking the Cryptic and the app name on your favourite app provider: Classic, Killer, Chess, Miracle, Thermo, Arrow, Sandwich, Domino and GAS 1 and 2, and brand-new Lines.
▶ SUDOKU PAD ◀ Input classic sudoku puzzles into our software. With 12 free puzzles:
iOS: apps.apple.com/us/app/svens-s...
Steam: store.steampowered.com/app/17...
Android: play.google.com/store/apps/de...
Amazon: Search for “SudokuPad”
▶ CTC FAN DISCORD SERVER◀
/ discord
▶ OUR VIDEO CATALOGUE - CATEGORISED WITH LINKS◀
tinyurl.com/CTCCatalogue
▶SEND US PUZZLES TO SOLVE/CONTACT US◀
[e-mail]
Snailmail: Mark Goodliffe, Box 102, 56 Gloucester Road, London SW7 4UB
▶FOLLOW US◀
Twitter: #crypticcracking
@crypticcracking
Instagram @crackingthecryptic
▶Credits◀
Music: Tim McCaskey (Guitar) or Lucy Audrin (Piano): Mozart's Sonata no 16; and Mark’s outro music by Riffclown.
SOFTWARE: Thanks to Sam Cappleman-Lynes and Sven Neumann
Logo: Melvyn Mainini
Opening Credits: Joel Blundell
▶ABOUT US◀
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. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times crossword championship and twice Senior World Champion in Sudoku, and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.
Thank you for watching!
Simon and Mark
▶ Contents ◀
0:00 Theme Music & News around the channel
2:48 Rules of today’s puzzle
3:59 Start Of Solve - Let's Get Cracking!

[@Chris.savvides]

What an absolute privilege to have my puzzle featured on the channel! I completely agree about the grammar and I apologise, to be honest I wasn’t sure how to edit it after it was published. I’ll be more careful if I set another…! Thank you to all for taking the time to solve it.

[@jdyerjdyer]

Loved another short and sweet one. So many on this channel are brutal. Nice to have one that even I can do in under 45 minutes. (38 for this one.) :)

[@laschlein9470]

Don't be silly, easy to mix up "proceed" and "precede". Great puzzle 👍

[@isidornimages]

I'll admit I haven't watched this channel for the last couple of weeks. I'm glad I popped in for this one. My 41 minute solve won't break any records, but I'm happy with it. I usually end up at about an hour with these puzzles in sub half hour videos, if I can solve them at all.

[@y_prime]

solved in 6:08 - nice pattern! a hidden useful thought based on the rules is that if you place a 1, you can put the 9 before it, so it works in reverse, and that helps

[@jurgenbaumann67]

My first number was R2C5. 2+3+4+x > 9 => R2C5 = 1

[@jeroenrl1438]

Right. Too bad he doesn't spot the impossibility of the 2 he pensilmarked.

[@RichSmith77]

I couldn't believe he started out pencil marking r2c5 with the options 123. He only ruled out 3 by independently concluding there couldn't be a 4 in the next cell (r2c6) first.

[@TimZ-rg1mf]

Me too.

[@VeritasUnae]

Adored the disambiguating arrow in bow 3, just like yourself Mark. A delightful puzzle that took me just under half an hour to solve myself. Really loved the interplay between 9s and 1s.

[@MattYDdraig]

13:47 I'm a huge fan of Escher so I loved the theme and the puzzle used it well.

[@darrenbent7601]

Ever since I first saw the Labyrinth movie back in 1986, I've always been a fan of the artwork of Escher. Quite interesting how one of his iconic pieces can be converted into a Sudoku puzzle.

[@Kirbyfan87827]

Finished in 20:58. This was a strange puzzle, but it's so similar to a thermo sudoku, my favorite variant, that I was able to pull through.

[@frankjiang1857]

Finished in 11:56. Fairly approachable and straightforward variant. Loved the Escher Thermos! Fun puzzle!

[@craftsmanwoodturner]

Loved this - I have several Escher prints on my walls, so it was wonderful to combine puzzling with art. I actually managed a solve in a reasonable time, too!

[@boydegg]

22:48 ... after failed first attempt. Awesome puzzle idea.

[@longwaytotipperary]

What an interesting concept for a sudoku puzzle!!

[@blobz-1]

Wow! What an amazing concept! Congrats on the feature!

[@jaredbitz]

29:24 for me. Very cool to think about thermos with undetermined lengths and starting points, but all arranged along a track.

[@RedBarchetta2019]

Great puzzle, Chris! thanks for setting!

[@57thorns]

Interesting variation and a nice 20 minute solve.

[@tomgalli1188]

The directions in the version I clicked on say that "each digit is proceeded by a larger number" which I read as "each digit is preceded by a larger number", which made the rules for the 9-1 relationship quite impossible. I probably spend 5 minutes trying to puzzle it out before taking a look at the video, where the rules say (much more reasonably, I think) that "each digit is followed by a larger number". It's quite odd, at least in America, to see "proceeded" used in this fashion. Might I suggest taking pity on those of us who aren't so linguistically savvy and changing it back to "followed"? Once I got past that, it was quite fun!

[@janetpiez3393]

Great puzzle! For some reason, I kept wanting to increase counter-clockwise, er, anti- clockwise!

[@stevieinselby]

I found the wording of the rules confusing, and initially tried to have the staircases going the wrong way, but it broke fairly quickly so I figured I must have misread them. _Edit_ - having just read some other comments, it looks like the rules have been amended to make them clearer, that explains why!

[@SimonStienen]

Beautiful one. Clocked in at 14:44, thanks!

[@Leslie_AF]

Oh my god, I got the *exact* same time 😅

[@grahamania]

00:22:03 for me. Fun puzzle, with a nice bit of logic to get going! Kind comment.

[@ChasePhillips7]

Great puzzle! I don't try many, but I tried and solved this one and really enjoyed it!

[@Timlagor]

Lovely. I even finished it by myself

[@pandurendradjaja8994]

Great concept and puzzle!

[@user-ds3ju2vb9p]

26:00 Not an amazing time, but a great puzzle, and I'm always happy when I can solve a puzzle from CTC without help from the video.

[@inspiringsand123]

Rules: 02:54 Let's Get Cracking: 04:04 What about this video's Top Tier Simarkisms?! Three In the Corner: 2x (20:45) Chocolate Teapot: 1x (20:19) And how about this video's Simarkisms?! Lovely: 6x (01:24, 03:54, 17:50, 17:50, 18:56, 21:38) Brilliant: 5x (00:16, 00:30, 01:10, 01:29, 01:47) By Sudoku: 4x (10:04, 14:38, 16:32, 16:55) Ah: 4x (11:14, 14:05, 15:53, 20:23) Obviously: 3x (01:08, 04:38, 08:42) Snake: 2x (01:31, 01:44) Intriguing: 2x (03:51, 21:51) Pencil Mark/mark: 2x (06:52, 16:46) Sorry: 1x (06:18) Home Straight: 1x (19:20) Fascinating: 1x (03:48) First Digit: 1x (09:55) Hang On: 1x (15:30) In Fact: 1x (13:26) We Can Do Better Than That: 1x (04:55) Fabulous: 1x (21:35) Most popular number(>9) and digit this video: Twenty Four, Seventy Eight, Ninety Eight (3 mentions) One (59 mentions) Antithesis Battles: Low (6) - High (1) Even (2) - Odd (0) Higher (2) - Lower (0) Row (9) - 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!

[@gregorysantos7624]

What a fun puzzle to solve! (30:52)

[@jasono8783]

10:48 ! Love it :)

[@zlatkakardaleva5738]

29:02. I started with c7r8 - the circle comes before the square and it has to be a larger digit so it can only be 9 and 1.

[@chris5619]

This video is almost shorter than today's wordle in a minute! Just kidding, love you Mark!

[@piasecznik]

16:57, not a great time, but interestingly had a *very* different solve path. I started by placing the 9 and 1-5 in the central box, which Mark didn't even get to until nearly the end of the puzzle. Probably more efficient to do it Mark's way, but I didn't even look at the easy numbers around the outer staircase until I had the inner one mostly figured out.

[@piarittersporn]

Beautiful and funny puzzle.

[@samgillmusic]

Great ruleset, this was fun solve - took me 31:42

[@thebitterfig9903]

Palindromic time of 23:32 for me, ending with what else but a 3 in the corner. A fun little puzzle.

[@whelmking6497]

21:02. Light and fun. Thanks!

[@mudscuffer]

Lovely puzzle. 19:02 for me

[@darthrainbows]

Escher thermos should be a new ruleset: like regular thermos, but 1 is considered greater than 9.

[@benjaminrealy5661]

12:35. Super easy. Barely an inconvenience

[@Rach881101]

17:12 for me. Nice puzzle!

[@eddieharwood7788]

What a lovely idea. I adore Escher's work so brilliantly illustrating the mobius strip. However the ruleset provided with Sven's sudoku pad rather spoiled my experience of it. "each digit is proceded by a larger digit in a clockwise direction" is such a weird way of putting it. To me it was disambiguously the opposite of what was meant, although as I type this I realise that it is not wrong. I read proceed as precede so it was my fault. However the wording on Mark's solution page was quite clear, so when I read that I scrapped my impossible interpretation and restarted.

[@davidh.4944]

3620@#1634. That was a smooth, pleasant solve for once, as opposed to all the ones I've had to struggle with in recent weeks. It only took a bit of thinking and careful pencil-marking to resolve everything. Nice.

[@anaayoung9142]

Good puzzle! And great thumbnail!! 😆

[@karlmortenlunna2417]

8:43 for me. Nice puzzle!

[@Oznej]

Took me 35:25 - what a lovely puzzle!

[@Antikas1989]

I didn't watch the video but I spent a few mins confused because in the sudokupad it says each number is "proceeded by a larger digit in the clockwise direction" instead of "followed by".

[@psiphiorg]

A great, clever puzzle! My time today was 7:04, solver number 8446.

[@Gonzalo_Garcia_]

7:07 for me. Great puzzle!!

[@nonyobisniss7928]

7:16 for me. This has to be the greatest disparity between a day's Mark and Simon videos, at least for my solve times if not their own. Simon's took me almost 2 hours if memory serves.

[@deszeldra]

I was only 2 seconds slower than Mark! Very proud :)

[@titusadduxas]

24:20 - Very enjoyable.

[@srwapo]

14:22, took a minute to see how to start, but went fast and linearly once I did.

[@letMeSayThatInIrish]

I hate to boast but yet again I observe that 800 people did this in a week while I did the same puzzle in half an hour entirely on my own!😏

[@kibels894]

The two boxes you called out at 3:45 actually were what you said by the end, hmm

[@philg6974]

Nice puzzle but the “proceeded by” confused me too

[@praematura]

This was a lot of fun, completed in 11:44 (conflict checker off), many thanks to Chris Savvides for a very cool puzzle!

[@themuffin437]

12:14, once I figured out the middle it was easy.

[@tonybrooms]

00:38:17

[@RoderickEtheria]

14:37, really quite easy.

[@RecreationalCynic]

27:58 for me

[@theredstoneengineer6934]

17:06 for me

[@bait6652]

Design begs the q? Are there 3 other solutions based on the stairs direction?? Interestingly you dont need the directions constraint...4 branches 1 breaks due to sum..2 break due to too high or too low digits on the loop. Reminds me of the roses/wheel puzzle that took simon 2hrs (oh 7-8 hidden thermos one

[@RADZIO895]

18:36 for me

[@jdyerjdyer]

R.I.P. Eight. Mark whacked you good and fair. lol

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

10:16 for me.

[@robertcousins2274]

20:33 for me

[@GilWright]

Thanks for explaining that the Patreon puzzle doesn't start with Sudoku. I took one look and then chucked it - not a fan of snake puzzles that have nothing to do with Sudoku.

[@stevesebzda570]

Im unclear here , @6:35 , "a 9 will always be followed by a 1," the rules say. Does that mean a "1 must always be preceded by a 9?" Why can't it go 8,1 in there for example? And "9" still possibly in the circle? Puzzle language? Thanks

[@RichSmith77]

It cannot go 8-1 because every digit other than 9 (so 8) has to be followed by a larger digit.

[@stevesebzda570]

@@RichSmith77 Oh, okay. Thanks. So, a 1 must be preceded by a 9 then? (Being, you're telling me it can't go 8-1) I haven't finished the vid yet, but it's about where the 9s go (like Mark was saying)? "A 1 preceded by a 9?" Puzzle (and puzzle language) 😆

[@RichSmith77]

@@stevesebzda570 Yep, that's right. Until you reach a 9, you have to keep ascending, and then, once you get to 9, you have to drop back down to 1. 👍

[@TurquoizeGoldscraper]

17:18 for me.

[@aoudazbidat6611]

Please anyone help me out here, it seems mark and all of you are assuming that if there is a 1 then there must be a 9 before it, but that is not how i understand the rules. Only if there is a 9 it has to be followed by 1. But if there is a 1 there can be say an 8 or 7 before it. As it doesnt have to be consecutive. Im only oartly into marks solve but it seems all his deductions so far are based on this false premise. For rxample at 8:27 he assumes 9 must be in one of two cells in row two so that he can then transition into a 1 but that's not the rule. What am I missing?

[@raminafchar4412]

Yes, same here with me. I learned to read the rules carefully. So I did not "reverse" the rule "a 9 is followed by a 1" to "a 9 is before a 1". Took me a while to came to a lot of 89 and a few 789 pairs. At the end I had a a final 78 pair that I could only resolve by putting a 9 before the 1. Wish that that would have been a bit clearer by the rules...

[@nikolausseydel1728]

Well, it follows from the rules: Any digit has to be followed by a larger one, except for 9, which is always followed by 1. If you have an 8 in a cell, the next cell must be 9 (otherwise it breaks the rule), and the one after the 9 must be a 1 (also according to the rules). What follows is: Any 1 must be preceeded by a 9, that's indeed not part of the rules, but you can deduce it from the rules!

[@stevieinselby]

Every digit going up the staircase must be higher than the previous digit, except in the case where 9 is followed by 1. That means that no other digit can reset back to 1, the only option to follow an 8 is to increase to a 9.

[@aoudazbidat6611]

Ah true true! Thanks for that!

[@DanielVita]

At around 6:10 I don't understand why he insists a 9 must be in the 'staircase' in box 5... Cannot 9 be in the circle in the very center and 1-8 is in 'staircase? I may be too drunk for this, hrumph...

[@highseven299]

It is not allowed to go from 8 to 1. So the 9-1 Pair has to be on the staircase.

[@LednacekZ]

19:31 for me. took me too long to crack the rules. i wasted a lot of time.

[@SenselessUsername]

I'm very confused you read "proceeded" 2x (around 3:25) when the text on the screen says "followed" --- and "proceeded" is what's currently written on the sudokupad instructions too. Proceeded is the opposite of followed!! [I started the solve by looking at the same arrow, but immediately concluding R2C7 necessarily was a 1 (as 2-3-4 breaks over the fourth digit) but that was wrong...]

[@benwhite5734]

"Proceed" is not a transitive verb; it's strictly intransitive in both British and American English. Therefore "proceeded by" in the rules as currently published is nonsensical. It should either be "succeeded by" or "followed by" (as it is in the video).

[@Steev42]

Yeah, I got the starting 9/1 pair, then re-read the rules and got very concerned so I had to check my result on just those two digits before I was comfortable proceeding.

[@samueldeandrade8535]

"Strictly intransitive"? This doesn't seem to be correct.

[@benwhite5734]

@@samueldeandrade8535 It is correct. I searched Merriam-Webster, Oxford, American Heritage, Collins English, even Wiktionary. None of them list it as a transitive verb.

[@samueldeandrade8535]

@@benwhite5734 "None of them list it as a transitive verb" Well, that's not what I asked you. Or, to be more precise, this doesn't answer my question. The conditions "verb not listed as transitive" and "verb listed as strictly intransitive" are not the same. The main part of my question, and of your comment, is the word "strictly". Is there such a thing as a "strictly intransitive verb"? And if there is, certainly "proceed" should NOT be STRICTLY intransitive. Because English speaking people say phrases like "you may proceed with ...". I can agree the word is NOT usually used with numbers. Only God knows why, because "preced" is used with numbers and it is the opposite/dual of "proceed", isn't it? And that's so weird, because the thing happens with "preceder" and "proceder" in Portuguese. We may say "1 precede 2", but we don't say "2 procede 1", we say "2 sucede 1". Man, I need a linguistics expert now. Hahahahaha. Why this happens?

[@nathanialblower9216]

I’ll proceed you!

[@dddnegre]

25 mins here…

[@Paolo_De_Leva]

The rules in the app are not the same as those in the description. 👉 In the app, _"proceeded by"_ (or even _"preceeded by")_ makes no sense. It should be _"followed by."_ By the way, this was a nice puzzle, although it turned out to be quite easy.

[@victorfinberg8595]

20 minutes for me ... surprisingly low

[@victorfinberg8595]

one thing to note: this is NOT a "pencil-marking" puzzle. it is a "find the critical digits" puzzle.