This Constructor's Favourite Puzzle

*** TODAY'S PUZZLE ***
Happy Birthday Scojo. You have a lot of fans out there in the sudoku world who wanted to see us attempt the puzzle of which you are (we're told) most proud! It's called Chocolate Banana Sandwiches and it boasts a 100% rating on Logic Masters. And, yes, it's absolutely brilliant (and quite hard!)
Play the puzzle at the link below:
sudokupad.app/f2DNr9b4tb
Rules:
Normal sudoku rules apply. Shade some cells so that every orthogonally connected group of shaded cells is rectangular, and every orthogonally connected group of unshaded cells is non-rectangular. (For the avoidance of doubt, a square is a rectangle.) A digit in a circle represents the number of cells in its shaded or unshaded group. Clues above a column represent the sum of any SHADED cells between the 1 and 9 in that column. Clues to the left of a row represent the sum of any UNSHADED cells between the 1 and 9 in that row.
Jane Street's Bug Bytes puzzle is available here:
www.janestreet.com/bug-byte/
(Simon's solve of this puzzle is on Patreon.)
*** NEW SUDOKU HUNT ON PATREON ***
We're delighted to share with you a brand new sudoku hunt themed around snake egg puzzles by Glum Hippo. If you've never tried snake egg logic puzzles before, prepare for serious fun - these sudokus are outstanding! Finish by May 20 to enter the competition!
Other treats on Patreon include:
- the Sumgeons & Diagrams sudoku by sunnyjum;
- Simon's latest forays into the world of Islands Of Insight;
- Mark's video looking at the new OneUp puzzle from Rodolfo Kurchan;
- his solve of Region Geometry by Emre Kolotoğlu (3hr 36min long...!);
- and Mark's latest solve of The Times Club Monthly cryptic crossword
www.patreon.com/crackingthecryptic
*** GET OUR FOG KICKSTARTER DELUXE & OUR BOOKS ***
Check out this link for the kickstarter books and Fog Novella we've created over the years:
coffeebean.games/product-category/cracking-the-cryptic/
▶ SUDOKU PAD - Use Our Software For Your Puzzles ◀
You can input classic sudoku puzzles into our software and help support Sven, the programmer responsible for the wonderful user interface we all use to play these puzzles everyday. The app also comes with 12 handmade puzzles from us:
iOS:
apps.apple.com/us/app/svens-sudokupad/id1570622073
Steam: store.steampowered.com/app/1706870/Svens_SudokuPad/
Android:
play.google.com/store/apps/details?id=com.svencodes.sudokupad
ALSO on Amazon: Search for “SudokuPad”
▶ Contents Of This Video ◀
0:00 Theme music & puzzle intro
1:34 Simon vs Bug Byte - a new Jane Street puzzle
2:00 Happy Birthdays
4:33 Rules
10:24 Start of Solve: Let's Get Cracking
▶ Contact Us ◀
Twitter: @Cracking The Cryptic
email: [e-mail]
Our PO Box address:
Simon Anthony & Mark Goodliffe
Box 102
56 Gloucester Road
London
SW7 4UB
(Please note to use our real names rather than 'Cracking The Cryptic'.)
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[@Scojo486]

Sorry about the confusion with rectangles vs squares. I was always taught that something being called a rectangle does not prevent it from being a square, but I'm glad it didn't affect the solve. Fun fact, this was the first puzzle I set entirely on paper! I was away on vacation without access to my computer so I printed out a bunch of blank sudoku grids and got to work. The key idea for the break in, which is that any 1xN rectangular shaded region needs to be sandwiched between non-rectangular unshaded regions of at least size N+1 on both sides, is what makes this puzzle one of my favorite puzzles that I've set. That property is what prevents every other 15 sum from working, even ignoring all the other clues in the grid. It had always made me a little sad that what I considered one of my best puzzles never really got to see the light of day, and it means so much that you gave it the opportunity to shine! Thank you so much for the birthday wishes, and for solving this!

[@anaayoung9142]

Happy Brithday!!! That was a great puzzle to watch Simon solve! Amazing that you did this on paper!!

[@andy-kg5fb]

Happy birthday!! Amazing puzzle, really loved it despite failing to solve it :)

[@nezarnassif2967]

SPOILER WARNING!!! Amazing Amazing Amazing puzzle... I love how it just flows like a symphony after you realize the fact that the shaded circles in column 5 have to be surrounded by larger unshaded circles. The circle that decided the order when trying to fit the 7 rectangle was also a perfect Beethoven note... Great job.

[@TheGreatSpanishBaldwin]

Fantastic puzzle and happy birthday! And don’t worry about the square thing, you’re 100% right.

[@RealCadde]

You shouldn't be sorry about the confusion, it's not your fault that some people don't understand language. Where it comes from and what it means. Rectangle originates from Latin Rectus + Angulus. Rectus - Straight, upright, direct, good, proper, correct. In essence, anything that doesn't deviate. It runs true. Angulus - Angle, corner, projection. So rectangle really does mean straight corner, or right angle. One could even compare it with a straight edge, the tool. It forms straight angles. Square originates from Latin Quadro. Which itself is a combination of two Latin words Quadrus (Square) and Quattuor (Four). It means "to make perfect" with four being implied, to square, fit with, put in order. It's like an obsessive person neatly arranging things inside a four cornered boundary that is perfect. All sides being equal. All edges are equilateral. A cube is a three dimensional square. Anyone claiming a rectangle can't be a square simply doesn't understand that a square is just a PERFECT rectangle. Perfect meaning all sides are equal. All lines are between two points. A line can curve unless you define it as parallel or straight. All triangles are made up of three angles, three corners. They don't have to be equilateral triangles. An equilateral triangle is to three, what a square is to four. All pentagons are made up of five angles, five corners. They don't have to be regular (all edges of equal length), an irregular pentagon is still a pentagon. Regular pentagons is to five, what a square is to four. And i could go on with hexagon, heptogon, octagon... n-gon. It would be a problem if you intended to have squares but wrote rectangles. I don't think anyone who sees a long rectangle would call it a square. Though i've met some illiterate people in the past. But even they know that a rectangle that doesn't have equal sides is not a square.

[@tremkl]

Disclaimer: If your chocolate banana sandwiches have turned green and gray, please do not eat them. They have gone bad. 😂

[@AlRoderick]

Bananas go from green to yellow to brown to black and green again.

[@jdyerjdyer]

It's okay if the green and gray is from pistachio nut butter.

[@shanem7573]

Mark could be on *Who wants to be a millionaire* and trying to phone a friend and Simon still wouldn't pick up the phone during a video 🤣

[@DrSpecialful]

I do enjoy how Simon in one puzzle will enjoy choosing the perfect colours, but in others completely reject the setters plans on water/land or chocolate/bananas.

[@tinakerr8163]

Yes, I couldn't imagine doing this in any other colours than yellow and brown.

[@angec9908]

In geometry, a square is a rectangle. A rectangle is a polygon with 4 sides and all interior angles = 90°. (This is pulled from my memory of learning this about 50 years ago but I believe it is correct.)

[@francoisduez601]

Indeed, it is still true 😅

[@CrazyIvanTR]

Yup. If anyone who's talking about a rectangle is not specifically excluding squares, then I'll have to assume they include it because squares are just a subset of rectangles. Also, I'd say that if anyone doesn't include squares in rectangles, then I don't accept that a one cell sized "region" can be a square and it's just a dot. Going with the same logic I'd also argue that a straight line of cells are just a line and not a rectangle. Anyway, thanks for reading my TED talk.

[@deathpigeon2]

A general point you can make about the center column that would force its digits faster is that every shaded cell must be surrounded on the top and bottom by two unshaded cells higher than them. The reason 456 didn't work is because, to frame them all, you need 4 digits higher than 456, but there are only 3. Similarly, 267 didn't work because there are only two digits higher than 6 and 7.

[@tremkl]

I’ll never understand people who argue a square is not a rectangle. Is a necklace not jewelry, just because there is a word for it’s specific type of jewelry?

[@donaldsnyder1543]

Maybe a square ⬛ is a circle 🔴?

[@delta3244]

It's related to Grice's Maxims of quantity and manner, I think. The Cooperative Principle applies in at least most places where English is spoken, so people expect all relevant information (quantity), and expect the avoidance of ambiguity (manner) in conversations, so expect that if a person says "rectangle," they said that because it would not be correct to say "square." This expectation that suits casual conversation could become part of how one understands the definitions of the words if one isn't exposed to the cases where squares must be considered as a special case of rectangles.

[@colej.banning2419]

​@@delta3244I was convinced that linguists called this phenomenon "q-type narrowing" but I can't find any references to that term on Google so I must have imagined it.

[@tremkl]

@@delta3244 Fair. If I was describing a single shape, and it was a square, I would be much more likely to call it a square than a rectangle. I kinda still stand by my jewelry analogy. If you’re talking about a particular piece of jewelry, it’s more accurate to call it a ring or a necklace or whatever, but none of them stop being jewelry.

[@delta3244]

@@colej.banning2419 "Q-based narrowing," perhaps? Bearing in mind that I'm not too knowledgable about linguistics, a quick search with no fact-checking brought me to something plausible-sounding called the Q-principle. Wikipedia cites it as a reformulation of Grice's Maxim of quantity (Q stands for Quantity), which states "Say as much as you can (given R), where R is a reformulation of the Maxim of relation stating "Say no more than you must (given Q)." When I was writing my original reply, I couldn't decide whether to pair relation or quantity with manner, where I was trying to get to "people attempt to avoid ambiguity by Q (always saying as much as they can without extending the length of the sentence) and R (which doesn't pair as well with manner, hence why I settled on Q)." That formulation of (R)elation and (Q)uantity expresses the concept I was trying to express very well without needing to awkwardly work through "avoiding ambiguity" in Manner, so I like it.

[@angec9908]

I don’t like when Simon calls himself stupid. I watched him work out the most intricate & complicated logic solutions to get a single cell. Meanwhile, I’m still trying to figure out what the rules mean.

[@aamocryp]

yeah, with this kinda self-disparaging there's always the question of "what are you saying to the people who are in the same boat or haven't even gotten where you are" like sure, you don't intend it as commentary on anyone else, but people will reflect it onto themselves bcs that's just how we work

[@uigrad]

I feel the same with the "sorry I'm so slow" comments. At one point in this puzzle, he put something like 12 digits in the puzzle in about 20 seconds, and then realizes he could have put in an 8 during the first half of that flurry of activity and says "Sorry I've been so slow." Don't be so hard on yourself, it makes us feel even more inferior!

[@biaberg3448]

I agree. If Simon is slow/ stupid, then there are no words to describe me.

[@easternbrown]

I think he's more kind of talking with himself when he does that. If Harry Kane hits the post from 20 yards out and gets annoyed with himself it's OK because he's Harry Kane, it's not a slight on the thousands watching who couldn't hit a barn door. Simon's disappointed not to achieve what he thinks he should be capable of, and kind of projects the disappointment with himself on his invisible conversation partner, the viewer.

[@okmarshall]

@@biaberg3448 Slower, more stupid? Just kidding :)

[@penningmeestercgkdelft9159]

Chocolate Banana, Chocolate Cake, Chocolate Teapot… I think I see some pattern in all this 😀

[@tommihaapanen846]

Interestingly the color of the pattern turns out to be gray 😅

[@jimhenry5552]

Oh, Bobbins. Bobbins McBobbins face. Hahahaha. I needed that.

[@emilywilliams3237]

I enjoyed watching this, and followed most of the logic - nevertheless, it is not going on my list to try immediately! It is too hard (though fascinating). Thanks, Simon!

[@marcbennett9232]

a square by definition is always a rectangle.

[@user-gj5uc4yx3i]

But it is never prime 😉

[@aikiseppuku]

Haha, that's a good one. Though obviously the area, the circumference and the sides of square can be prime (in different settings).

[@theendicott2838]

A square, still by that same definition actually, is always a rhombus. I love geometry.

[@benwhite5734]

"I fear we have lucked into the right answer here." Turned out not to be the case, but that's still a great line.

[@dekomali]

I would never had solved it without Simon. Especially at the start-up and the whole thinking process. This is the process I almost always go through. Start up with Simon until I do understand how to go about the puzzle. Middle part I go back and forth between getting Simons help and solving on my own. If I manage most on my own I am pleased. Then nearer to the end however I am generally faster than Simon.

[@grahamania]

00:56:07 for me. That was a great puzzle. Loved the way the shading and circles worked together! Kind comment.

[@justinfarmer8371]

I’m waiting for someone to make a sudoku puzzle that doesn’t need sudoku to solve it

[@nathanialblower9216]

Starting @34:45 Simon says that r2c5 could not be 9 because the whole row would be shaded. This is wrong. The 9 would be unshaded, and its region could be just about any shape. The reason it couldn’t be a 9 is that there wouldn’t be enough cells to fit in 8, 7, 6, 5, 4 (to add to 30) between the 9 and the 1 in row 2 (something I’m pretty sure Simon had already deduced earlier anyway, but just forgot)

[@RealCadde]

Yeah i reacted to that as well. Simon does have the most crazy sentences when he thinks one thing and says a whole other thing.

[@stef4391]

I am convinced Simon has a blindness to 6's after watching this puzzle :D

[@inspiringsand123]

Rules: 04:58 Let's Get Cracking: 10:29 Simon's time: 1h1m34s Puzzle Solved: 1:12:03 What about this video's Top Tier Simarkisms?! Bobbins: 3x (16:36, 16:39, 16:39) Three In the Corner: 3x (51:33, 54:59, 1:09:39) The Secret: 2x (17:30, 17:37) Knowledge Bomb: 1x (10:41) And how about this video's Simarkisms?! Ah: 14x (11:37, 13:32, 16:24, 16:32, 27:17, 28:38, 28:45, 32:17, 34:23, 37:20, 45:08, 56:42, 1:08:06, 1:08:58) Hang On: 11x (09:07, 09:23, 13:32, 23:10, 41:18, 43:12, 43:23, 44:29, 51:48, 1:08:35) Sorry: 9x (21:42, 33:46, 38:39, 43:43, 44:56, 45:12, 1:03:29, 1:05:37, 1:11:08) Weird: 8x (19:54, 32:24, 40:39, 46:53, 48:57, 49:22, 56:47, 56:57) Clever: 7x (23:23, 28:49, 32:21, 43:49, 1:12:59, 1:13:01, 1:13:01) Beautiful: 5x (00:20, 00:24, 33:15, 43:34, 56:34) In Fact: 5x (32:56, 34:51, 40:17, 57:42, 58:18) Shouting: 4x (02:26, 02:56, 03:13, 03:46) Nature: 4x (1:00:25, 1:00:27, 1:01:23, 1:01:55) Cake!: 4x (01:28, 02:20, 03:01, 03:04) Good Grief: 3x (10:21, 54:40, 58:48) Naked Single: 3x (54:15, 1:05:09, 1:10:40) Brilliant: 3x (00:45, 1:12:12, 1:12:12) Obviously: 3x (10:34, 10:59, 1:12:43) Whoopsie: 3x (26:41, 26:45, 1:10:46) Symmetry: 3x (26:41, 28:01, 28:14) Bother: 2x (20:04, 29:34) I Have no Clue: 2x (31:10, 41:36) Lovely: 2x (51:18, 54:50) By Sudoku: 2x (1:00:43, 1:09:20) Wow: 2x (08:46, 43:34) What Does This Mean?: 2x (11:26, 41:36) Nonsense: 1x (07:53) Stuck: 1x (01:56) I've Got It!: 1x (29:40) Disappointing: 1x (1:02:41) Pregnant pause: 1x (1:08:56) Pencil Mark/mark: 1x (1:11:11) Most popular number(>9), digit and colour this video: Thirty (19 mentions) Nine (111 mentions) Green (32 mentions) Antithesis Battles: High (2) - Low (2) Even (9) - Odd (0) Shaded (62) - Unshaded (39) Higher (2) - Lower (0) Inside (4) - Outside (3) Row (33) - Column (31) 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!

[@MattYDdraig]

48:10 Some clever tricks in the puzzle and a lot of confusion in my head. Mental note: must remember not to try including the 1 in the sandwich sum!!!

[@HunterJE]

29:47 the 19 “crusts” in c5 needing to be different colors AND needing to have three shaded cells between them fixes the distance between them; after that ruling 19 out of r2c5 places the crusts in that column exactly…

[@afrayedknot81]

1:05:05 "How does that get resolved actually, that's very strange". **Immediately highlights the 6789 quad

[@ericpraline1302]

I really enjoyed that, thanks, more so because when I looked at it yesterday I made as much progress as an arthritic ant pushing a ten ton weight up a very steep hill. When I came back to it today some things clicked. Great ruleset.

[@PinkBear-zz4mi]

He says it's outrageous, making him do sudoku in a sudoku puzzle.

[@MarushiaDark316]

Is a chocolate banana a banana covered in chocolate or a banana made of chocolate?

[@ErikLeppen]

49:35 "Now all that we have to do is...something"

[@Sergi4]

It felt so complicated while I was in process of solving that I was so unsure till the end that I was doing everything right and was happily surprised in the end that I solved it correctly. Great puzzle)

[@studgerbil9081]

I still maintain that Simon needs an intern to clean up the Sudoku at the end, after his brilliant deductions and strategizing.

[@tessabrisac7423]

😂😂😂

[@stangerrits6712]

Yeah, an eager junior who will actually cross check all pencil marks :D

[@filkube8540]

Simon's so incredibly smart and it's so annoying when his brain apparently refuses to see the obvious sudoku logic (like the 6 in box 5 seeing the 6s in C3 etc)

[@Manigo1743]

I don't understand the confusion people have with rectangles and squares. A rectangle is a shape with four right angle corners. Why should it suddenly not be a rectangle just because all the sides are the same length? A square is always a rectangle.

[@biaberg3448]

Simon, you are a very clever man!

[@bjslater4199]

9 needs to be next to 7 which needs to be next to 8, 5 minutes, repeat. Then we go off on a tangent, then the 8 goes in.

[@josephulton]

Every square is a rectangle, but not all rectangles are squares.

[@kamill6120]

These rules were not very clear to me. This part with "between 1 and 9" - I mistunderstood it and I thought it is not about placement of 1 and 9, but rather from set 2-8 (:

[@donaldsnyder1543]

The poor lonely shaded circle finally gets it's number.

[@sams5963]

Maybe you do this on patreon, but I would love to see you have a discussion with the setter after he sees you solve the puzzle

[@Axxon2000]

It's always fun to watch a "zetamath reacts to Simon solving [zetamath puzzle]" I'll watch that after I have watched Simon's solve. You get a good look at both the setting of the puzzle and how well Simon follows the intended path.

[@Gonzalo_Garcia_]

28:59 for me. Very unusual logic, but that only made it even more interesting. Fantastic puzzle!!

[@MAUOMBO]

Squares are a subset of rectangles Rectangles are a subset of parallelograms

[@pR0stYp3]

Is a square a rectangle? Well, only if Plato is a human.

[@Imrtlpanda]

From what I was taught, all squares are rectangles; not all rectangles are squares.

[@oneeyedman4431]

🤔 loved the video without understanding any of the column 5 logic. Groundhog day again for me on CtC 😂

[@markheisler5118]

All squares are rectangles, but not all rectangles are squares!

[@anaayoung9142]

Thanks for using your brains cells to solve this one because I would not be able to 😅

[@Squishy3757]

A square is a rectangle, simple as that.

[@al129]

A square is a rectangle but a rectangle is not a square.... the difference in definition is that a square has 4 equal length sides, whereas a rectangle doesn't have a stipulated side length just the 4 interior 90 degree angles. .

[@RecreationalCynic]

Solved it in 106:28 and enjoyed it, though I'm more of a peanut butter and banana guy myself

[@dudbike]

Banana and peanut butter for the main course. Banana and chocolate for dessert.

[@henriknobinder7395]

All squares are rectangles. Not all rectangles are squares. Squares are a subset of rectangles.

[@LednacekZ]

i had no idea what the rules where. It did not translate for me at all.

[@Ardalambdion]

Hi. I am looking for a puzzle where Simon has to place sum of 10s at lines, but he can only use a configuration once. Say that he has used 37, no line can be used for 37 again.

[@deadeaded]

Are you sure it was 10? There's a puzzle like that with 15 lines. The video is called "The Sudoku With Only 4 Known Solvers."

[@Ardalambdion]

@@deadeaded Not that one.

[@Ardalambdion]

Found it, Jay Dyer X-Clusitivity, Counting to 10 At Its MOST FAscinating.

[@theredstoneengineer6934]

42:11 for me

[@MariaVlasiou]

Let's go!

[@jontis123]

Thank you so much for the birthday wishes to Helene! The chocolate cake was very appreciated, and inspired by you, so thank you for that too. We pronounce her name like "Helen" in English

[@travisporco]

circa 34:00 why couldn't that have been a 2 in r2c5?

[@RichSmith77]

Immediately preceding this, he'd shown that the 7, of a 267 combo, couldn't go in either of the two shaded cells not adjacent to the 9. The 7 had to go in r2c5, if the 15 sum was 2+6+7.

[@caiodavi9829]

simon Orz

[@hrbattenfeld]

Kind

[@RoderickEtheria]

Why is there no rule that states that regions of the same type(shaded or unshaded) cannot touch?

[@sjm6280]

By definition, a shaded/unshaded group is a complete collection of orthogonally adjacent shaded/unshaded cells The cells from two adjacent shaded/unshaded "groups" would indeed belong to a same single group

[@RoderickEtheria]

@@sjm6280 You have other puzzles that make that distinction.

[@RichSmith77]

​​@@RoderickEtheriaI think you only have that specified if regions are part of the rule set for some other reason. Such as chaos construction puzzles where you're asked to construct regions with some property, and then perhaps shade some of the regions. Here, we don't have any separate definition of "region". We just have groups of shaded cells and groups of unshaded cells. If two similar groups abut, then they just become a larger group.

[@phrozenonetwo]

Yeah, at 15:58, he seems to assume that regions of the same type can't touch, but the rules do not mention it. Quite significant change to how to solve it. I need to keep watching to see if he addresses that later on.

[@RichSmith77]

@@phrozenonetwo The rules don't need to state it. It's like if you tip one pile of sand onto a second pile of sand. You no longer have two piles of sand. You just have one larger pile of sand. Here, if you connect one group of orthogonally connected shaded cells to a second group of orthogonally connected shaded cells, you no longer have two groups of connected shaded cells. You just have one larger group of orthogonally connected cells.

[@angec9908]

Zeroth like again 🎉