The Rat Race by Marty Sears

[@martysears]

Hi Simon, lovely surprise to see this featured this evening! Thanks again for another thoroughly entertaining solve. I have been beavering away on this series for several months so it has been very exciting for me to finally publish the first episode and share it with everyone, and especially to see it is already getting a good response. The lead protagonist is named after Sarah (AKA Ratfinkz), an excellent member of the sudoku community who is delightfully lovely and kind to everyone, as well as having a very cheeky sense of humour. Oh and she also loves rats. She has even been featured on the channel before - her puzzle Diamond Mining (which is very clever and fun) was solved by Mark. She has always been very supportive of my puzzles, and it never fails to puts a smile on my face chatting with her. I've always enjoyed mazes... I used to make my parents take me to the castles that had hedge mazes outside them, and for a long time when I was young I used to love designing them and made several whole books of mazes over the years, some of which are currently under my bed. So anyone who knows me well would probably think I was bound to do this mash-up of maze and sudoku at some point. The first Rat Run puzzle I made was back in February and will probably end up being episode 7. It's quite a tricky one and I decided I wanted to make a series with a gradual learning curve that adds in different elements one by one. So since then I've gone back and made some easier ones, including this one. I was originally going to have one of the later puzzles use this prime number rule, but when I thought of the title 'Primer' it seemed perfect to use it in the opening episode instead, and I thought the difficulty level of this 6x6 version was just right. Beware though Finkz, they won't stay at 2-star difficulty for long ;) 🐀

[@sarahnash7174]

Oh, go away with your lovely comments making me 😭 😳😳 All I can say is that you are pretty darn awesome yourself and I love our chats and banter! Thank you for always accepting me, goofiness and all! And, thank you for this incredibly special and thoughtful puzzle! I can't wait to do the next one!

[@pouletbelette]

Thanks again, Marty! Very nice puzzle.

[@katiekawaii]

I _love_ the Idea of gradually increasing the difficulty step by step like that. I can't wait to do the rest of them!

[@annek3296]

I have to wonder though - who actually is the Rat in this puzzle? Is it Finkz ? Or is it actually us CTC Sudoku-ists, sniffing our way through the maze??🐀🐀🐀

[@emilywilliams3237]

This flavor text and situation that you've set up in this puzzle is absolutely fun and funny - thanks so much, Marty! I look forward to watching Simon or Mark solve another one!

[@sarahnash7174]

I feel so incredibly honoured to be the rat in this beautiful puzzle! 💜 Thank you so much Simon for solving it, and thank you Marty for everything 💜

[@Ardalambdion]

How nice of Simon to dress up for the rodent.

[@lukasmbrito]

How mice of Simon... Sorry, I couldn't resist.

[@Pulsar77]

It's amazing how Marty is not only extremely prolific but also highly original and consistently great. He's published 72 puzzles on LMD since April 2023, all of which have a rating above 90%. I started setting at the same time, and I've only come up with 4 half-decent puzzles... some people seem to have a special brain for this stuff.

[@RichSmith77]

Marty is so original and prolific, he will, from time to time, leave a reply to one person's query under someone else's comment to see If we can work it out. 🙂

[@martysears]

@@RichSmith77 whoopsy! not sure how I managed to do that 😅 have deleted and moved to the right place now. Thanks for the kind words @Pulsar77

[@Pulsar77]

@@martysears I solved your 'anti-kropki' puzzle on LMD last week (I posted a comment). Beautiful setting. I don't know how you do it, but keep doing it!

[@MarkBennet10001]

This is ridiculous - the quality of puzzles on the channel, I mean - another beauty, and the next one in the series is also excellent ...

[@Hakucho64]

Ooo, link please?

[@xanderpizza2759]

​@@Hakucho64 here's the second one :) I came looking for the third but I'm not sure if it's out yet

[@Hakucho64]

@@xanderpizza2759 I'm not seeing the link

[@xanderpizza2759]

@@Hakucho64 Sorry it seems to be deleting my replies that have the link, here's the code instead: a7jn2d1357

[@xanderpizza2759]

@@Hakucho64 sorry it keeps deleting my comments with it so here's the last part instead a7jn2d1357

[@emiknits02]

Even though I hear it nearly every day, I'm always so happy when Simon tells me I'm one of his favourite people:)

[@smahoney1212]

And Simon (and Mark) are among our favorite people :)

[@chocolateboy300]

I finished in 44 minutes. I thought I had misunderstood the rules and broke the puzzle. Rereading it, I realized my stupidity that the center of the puzzle has no walls and can cross. I, then, thought that I broke it again until I happily realized that 2 is a prime number. I knew that the grid was going to alternate between even and odd and realizing that 1 and 1 equals 2 was an amazing feeling. I really enjoyed this puzzle and the storytelling. I look forward to more from the great Marty. Great Puzzle!

[@jpryan90]

I too, thought I broke the middle before realizing I could make it double 1.

[@rubenverg]

welcome to today's episode of "are the digits moving?"

[@l3zl13]

@25:35 Simon missed the possibility that the route could have gone to the 2 at c2r6 instead of a 6. It would have failed on the next step, but still.

[@PH34RB]

Also got stuck there and came to the video for help xD We all miss some! If you solve the 4s and the top path is chosen, then you get a 3 in the top left corner but there was already a 3 in r4c1: breaks.

[@stephenvale2624]

I am astonished at how many ways the setters can create rules/puzzles that are almost breathtakingly impossibe to imagine.

[@hipparchos]

I am ashamed to admit that I spent a good five minutes wondering why cell r3c3 couldn't be 8 since 21-8=13

[@Ryan_Britt]

Interesting how different people can approach things in different ways. I didn't think about parity at all and instead used a German Whispers approach, thinking about which digits can "pair" with others. For example, any 3 on the line MUST be flanked by 2 and 4, and that fixes the position of 3 in the left-middle box.

[@davidrattner9]

Your joy and enthusiasm in solving Simon is such an amazing constant from you! Every day you are doing something you love!

[@grahamania]

00:23:17 for me. Loved the puzzle! Always fun to have a little story to go along with the logic :) Kind comment.

[@blobz-1]

Congratulations on an a-MAZE-ing puzzle, Marty! Such fun to see Finkz the Rat featured :)

[@katiekawaii]

Please do the rest of the series, Simon!

[@thejuggler42]

Great to see this one on the channel! When I solved it myself, I was stumped for a good long while in the middle because I foolishly had it in my head that there were no even prime numbers. Another great puzzle from Marty.

[@srwapo]

17:24, glad I remembered the prime box sum rule when I was looking at box 2, thought I broke it at the end forgetting the line could move diagonally. Actually, thought I also broke it at the beginning before I remembered 2 is prime. The note after the solve sure threatens a harder puzzle with this rule set!

[@seanb7807]

A wonderful idea, and great execution! Excited for bigger versions!

[@AaronPriceColby]

Great puzzle, couldn't see the breaking 5/6 combo in row two to save my life!

[@Praetarius]

24:55 Why has the path to go from the 1 into the 6? It could still go into the 2 below it at that point.

[@Esperi74]

The next cell would have to be a 3, making a total of 10 in box 5 and (knowledge bomb) 10 is not prime. Additionally, there would be nowhere to go after the 3, as 3-5 and 3-6 are both not prime.

[@aawillma]

Just a good guess. It becomes clear very quickly once the 5 is forced but yeah, at that point it could have gone into the 2.

[@stevieinselby]

It is definitely a possibility that Simon should have considered, but the way to show that it can't be is that if the path drops down to the 2 then its next digit must be a 3 in c3, and then the puzzle breaks. Because either it leaves box 5 at that point, putting a total of 10 on the path which is not prime, or it moves to the 6 for a 9-pair and a 16-box-total which is even worse.

[@danielszanto2955]

The parity of the line would be wrong, but it was not stated in the video for sure. (There must be an odd number of odd cells on the path in every box.)

[@craig--]

Simon hates the word "lucky" for some reason, but in this case Simon got lucky.

[@DanielA-uk9qg]

It’s interesting to me that you always define “orthogonal” as sharing an edge- I’ve always just thought of it as the opposite of diagonal. As in, up down left right. Seems like a simpler way to explain it haha

[@craig--]

I agree, especially in this puzzle since "sharing an edge" doesn't make sense when we're talking about a line between the centers of cells.

[@stangerrits6712]

Indeed. In a filomino or chaos construction sudoke, or any other puzzle where you need to draw orthogonally connected regions, Simon’s description makes sense. But for line drawing or snake puzzle, moving horizontally and vertically or something like that would be much clearer I think.

[@iabervon]

It's preparation for Sunday GAPP puzzles, where sometimes cells are triangles and not all of those directions are necessarily orthogonal.

[@gloriagarcia3761]

I always think of it as "vertical and horizontal", I guess every brain has a preferred way of seeing it which is quite interesting 😂

[@manudude02]

I can't get enough of a puzzle that looks impossible, and then falls into place much faster than expected.

[@Coyotek4]

9:56 ... yeah, sets like this will bring me back Nice puzzle!

[@frankjiang1857]

Finished in 19:00. Interesting ruleset which leads to some interesting constraints in path. Fun puzzle!

[@artsenor254]

I love primes, I love mazes, I love mice and rats, and I love the weird rules these guys always come up with. Can't wait for the next one !

[@LaatiMafia]

In before the Rat Run 2 that: Is a 9x9. Includes doublers. Is covered in fog. Has two cats patrolling the board. Counts 1 as a prime.

[@jinkela7295]

Rat run 2 is indeed an 8x8 sudoku where the constraint of the path is that adjacent cells on the path sum to at least 10

[@RichSmith77]

I reached Simon's position @21:30 and then got stuck because I forgot the rule about the entire path in a box having to be prime. Instead of using that to determine box 2, the straightforward way, I ended up noticing that if r2c3 was a 3 then it forced 2 and 1 to it's right, which left no fill for r2c2. But it took far too long to spot. (It did mean I could complete it without ever remembering the box rule, though.)

[@martysears]

haha I actually did it the same way as you. I didn't think of the 234 thing either! I just noticed that r2c2 must be 2 or 3, so broke if a 2 is placed next to a 3 elsewhere in the row

[@elizabethshort9632]

I was stuck for ages and couldn't spot the 56 issue in row 2. So frustrating that I stare at a puzzle for ages to come back here and Simon sees it with barely breaking stride 😂

[@themuffin437]

11:58 for me, once I figured out that the parity of digits alternated it was simple

[@tBagley43]

32:06 odd/even coloring is very helpful for this one

[@Aliessil]

Finished in 16:52. Really enjoyed that and looking forward to the next one!

[@wanderlustwarrior]

23:13 for me. That was a challenge to shift my brain over to, but very fun and not too hard once you get into it!

[@nomore6167]

Since you seem to be showcasing puzzles involving prime numbers with a fair frequency, it would be helpful if the solving app had a section showing prime numbers so those of us who don't know them by heart don't need to look them up every time.

[@Yttria]

Loved it. Lots of fun with new and interesting logic. Not too difficult. Finished in 15:46.

[@Gonzalo_Garcia_]

10:59 for me. Nice puzzle! I bet will see more of this series soon.

[@linforcer]

I got stuck on this puzzle because of a niggle I have with the rules. I took "In this experiment, any two adjacent cells along the correct path must sum to a prime number." to mean that when you move diagonally, the digits on the path end up not adjacent and no longer need to make a prime.

[@TurquoizeGoldscraper]

19:04 for me - I got a little stuck as I was trying to figure out how to finish the line at the bottom when I had one more bit of logic near the top to work out.

[@MattYDdraig]

16:03 Awesome puzzle idea.

[@six_5000]

Took me 45:28… kinda reminded me of that game on windows 95/98 where you’re a mouse pushing blocks the get the cheese and trap the cats 🐭 🧀 🐈

[@srwapo]

Oh, no, now I want to go hunt down a game I totally forgot about.

[@Krewph]

Sokoban?

[@six_5000]

@@srwapo @Krewph looked it up, I guess it was in an add on pack but basically yeah a sokoban variant en.wikipedia.org/wiki/Rodent%27s_Revenge

[@Lykrast]

30:25 lovely puzzle! Only needed the video once to realize a thing but then managed all on my own!! (that the consecutive prime sum means it alternates between odd and even, except for 1-1)

[@pah23]

I challenge Sven to get the mouse(Finkz) to move along the drawn path at the end of the puzzle to eat the cake please and thanks 🙏🤗

[@davidrattner9]

Loving this puzzle already. Just creativeness from you Marty! Did you name the Rat after Sarah? 😉

[@martysears]

Had to be done David :) thanks for all your encouragement and support, I always appreciate the nice comments you leave

[@Kirbyfan87827]

Finished in 31:32 with help from the video.

[@Henhenz1]

Interesting how the numbers in the completed puzzle almost have 180 degree rotational symmetry (the 2s and 3s are swapped outside of the middle two rows). Wonder if that's a byproduct of the constraints or a starting point from the setter.

[@martysears]

Great spot! D'ya know what, I hadn't actually noticed that until you just pointed it out. I think it's a byproduct of the fact the two middle rows are purposely rotationally symmetrical. My starting point was that I wanted to include the sneakiness with the 1+1 diagonal, and the best way of forcing that was to set up two adjacent boxes where you needed to visit three odd numbers in both. Once these middle two rows were in place, sudoku largely filled in the rest, I just needed to add a couple more walls and the whole thing was forced.

[@aberrant322]

proud to be one of simon's favorite people!

[@alanclarke4646]

23:45 for me. I used a pen and paper to write down all possible prime dominoes, and used them to work out the only possible 5 digit chain for box 4 ( and 3), so my first two digits were different from Simon's.

[@victorfinberg8595]

20:00 next step: goodliffe the remaining cells. simon refuses. finkz starves

[@petrie911]

Don't trust them Finkz. The cake is a lie! (Now I'm hoping future mazes have portals.)

[@piarittersporn]

Wonderful little puzzle.

[@fylosofer]

That was a lot of fun. Really liked that puzzle.

[@PauxloE]

Found this after number 5. Still, it took me 48:50. I like prime numbers, so that's a bit surprising. I started out by drawing a graph of the numbers 1-6, with connections where they add up to a prime number. Then looked into which sets of 3, 4, 5 connected numbers can add up to a prime. (Only after the solve I figured out that a 4-cell set of sum 11 or 13 could be possible by dipping out of a box and back in. Not sure if I cheated by not considering that.)

[@markthompson2874]

Generally I pause the video until I get stuck. I started freaking out when Simon started putting 4's in the puzzles that didn't exist since I had already finished the 4's.

[@TheRedReid]

22:19 for me

[@57thorns]

I think the ending need to be a but more stringent. 123 is a valid move, however, looking from the end, the 35 cells has to go into one of three 36 cells, which is why it is a 5. This solved all the digits. And now the 5 has to go to the 6, and then to the 1.

[@martysears]

correct :)

[@kopo1]

I didn't quite get the rules at first. This rule: "any two adjacent cells along the correct path must sum to a prime number." The middle path goes diagonal, not adjacent?? So I thought the sum doesn't need to be prime number.

[@Schnitzelmampfer]

I'm so excited for the next maze!

[@psiphiorg]

A fun concept, and a great solve! My time today was 9:12, solver number 6900 (nice hundred!).

[@psiphiorg]

And watching the video, I almost immediately see that I made a lucky mistake. I had assumed the correct path through box 2, because the alternative would go through all six cells (or so my brain assumed). In fact, the other path could have worked because it wouldn't use all six cells. So this should have taken me longer to resolve that ambiguity.

[@AMOE1987]

The 'Controversy' can be cleared. 'If you do the math' of Keily turning 38... on the year of birth, it WAS a Friday, hence Friday 13th. T'was a little puzzle to solve!

[@JohnGottschalk]

This one was tricky, but i liked using graph theory to solve it.

[@Laezar1]

So many prime number puzzles recently, I never know how to deal with them

[@W.Andersson]

25:19.. Isn't the 2 underneath an option?

[@marcodossantos5366]

no, because the next number would be 6 or 3, 6+2 is not prime. As for the 3, the box would not be prime because 4+1+2+3 adds up to 10

[@W.Andersson]

@@marcodossantos5366 Of course it breaks, but Simon is always good at explaining why he does everything logically. Felt like an oversight to me.

[@RichSmith77]

​@@W.AnderssonYes. At 24:53 he just asserts that "after the 1 it needs to be an even number, which will be a 6". He gives no attempt at an explanation of why it has to be 6, when there's also a 2 below. It's so quick, I don't believe Simon considers the 2 below. He's just focused on moving Finkz to the right, towards the cupcake. (For me, it was easier to complete the path from the cupcake end. It had to exit to 5, as there was no next move from a 3. Sudoku filled in the rest of the digits, and the path then went from 5 to 6 to 1.)

[@martysears]

@@RichSmith77 Yes Rich you're right. Looking at options backwards from the cupcake at this point was the way I did it too

[@LyuboRyuk]

Fun ti watch

[@anaayoung9142]

Finkz is a very smart rat, he even know prime numbers! 😅

[@PsychoSoldierPrometheus]

Loved this!

[@longwaytotipperary]

Enjoyed the puzzle!

[@przemekmajewski1]

funny little 10 minutes puzzle ;D

[@RoderickEtheria]

16:28 solve.

[@Tepalus]

Does anyone remember what the Sudoku was called where Simon had to build it first himself? :)

[@martysears]

Setter's Day Off?

[@Tepalus]

@@martysears Thanks a lot!! :D

[@victorfinberg8595]

25:15 the roundabout path is still available ...

[@KevFrost]

Gods damnation to those 1 spoiling my bishop move parity colour scheme

[@martysears]

You will like episode 5 :)

[@mareksroka5629]

ok, I totally missed the "r2c4 cannot be 6, because that would put 5 in r2c3 and break r2c1". Instead I had to do some insane deduction about box 5: - Determine that Finkz can only visit 3 cells there (5 cells: not possible. We know that r6c1 is not on it, because neither 5 or 6 can follow 4 ; 4 cells don't work either, because that would be 2 odds and 2 evens, summing to a non-2 even number) - Only 4+1+6 works - This, coupled with the fact that one of the two last cells in the path has to be 2, solves the rest of the puzzle

[@titirenee]

Titi's Time: 11:54

[@Telixion]

Will you be continuing Braid?

[@longwaytotipperary]

Wondering about that also. 🤔

[@dannstarrjp]

The rules are unclear, I don’t wanna watch the video before I solve it myself, but it doesn’t say precisely what happens if the line enters the same box twice. What adds to a prime number then? Each entrance individually or both lines together? It’s very important because that determines whether the whole box can ever be filled completely with path cells or not

[@farbiarnarrr4767]

00:51:14

[@Timlagor]

Didn't feel like you earned the final 6 (couldn't be the 2 but only for reasons you didn't give)

[@raydarable]

Is it bad I forgot two was a prime number while trying to solve this?

[@iceberg54321]

Mmm, saying thick walls is not a good rule. I could take the Light purple around the grid as the thick wall of the maze wall, or the combined dark and light purple, or the dark purple, or indeed the box boundaries all as thick walls, as it just says think walls without qualifiers. So the cell boundary walls inside a box, could be the non-thick ones, freeing up the other walls to your interpretation. So I could run around the outside of the maze, go into the 1, in box 6 and then to the 2 in box 6, and that is also a correct solution if the light purple is the thick wall. If I take all of them all thick, except the cell walls inside a box, then there is no solution.

[@RichSmith77]

It doesn't just say thick walls though. It says thick MAZE walls. If you add in the light purple surround, it doesn't change anything. Beyond that, there's clearly only one set of thick lines in the grid that form a maze.

[@iceberg54321]

@@RichSmith77 The entire puzzle is part of the maze, so all the walls are maze walls.

[@iceberg54321]

If I had a maze of hedges, and put brick walls inside the maze, cutting off part of the paths, then those would also be maze walls.

[@iceberg54321]

If I put brick walls for the very outside of the maze, those would also be maze walls.

[@RichSmith77]

@@iceberg54321 If you only have hedges/brick walls around the outside of the grid, you don't have a maze. You have a square. If you add walls so that you cannot get from the start to the end, you also do not have a maze. No one with any understanding of what maze is can look at this grid and be in any doubt as to which lines are forming the maze walls.

[@Mason-lr5dz]

Hit a snag and I think it might be because I misread the rules. Without spoiling, can someone tell me - does the "adjacent" part of the test constraint mean 2 cells that lie one after the other on the path, or adjacency in the more classical sense? Do diagonals count or just orthogonal adjacency?

[@martysears]

Hi Mason, adjacent along the path means two cells that come one immediately after the other along the path, whether orthogonal or diagonal

[@Mason-lr5dz]

@@martysears The setter himself, how exciting. Thanks Marty!

[@Krewph]

That one was hard for me, took me 3h! 😧

[@theredstoneengineer6934]

15:01 for me

[@LednacekZ]

11:12 for me. horrible solve. it really helps when you know 1st grade maths.

[@Lumeth]

Simon, pertaining to your "rodent-like mind": Do you by any chance like the movie "Flushed Away" by the makers of Wallace&Gromit?

[@tomhoward4906]

The digits 1 through 6 all appear on Simon’s path, so the final rule says they should sum to a prime. Yet they sum to 21.

[@martysears]

There isn’t any 3x2 box where all 6 digits lie on the path…

[@tomhoward4906]

All six digits appear somewhere on the path. Or are we suppose to be using more than just the digits 1-6?

[@martysears]

@@tomhoward4906 it is just the digits 1-6. But the rules say “all digits within a marked 3x2 box”, not all digits in the whole grid. So you can’t have all 6 digits in one box lie on the path because that would add to 21, not prime. You couldn’t have a 2 and a 4 be the only digits on the path within a box, because that would add to 6, not prime.

[@tomhoward4906]

So instead of saying “that lie anywhere on the correct path” it should say something that “that lie on the correct path within the same box”. The word “anywhere” made it sound like you were including instances of the digit lying on the path even outside of that box.

[@martysears]

@@tomhoward4906 fair enough thank you for this feedback, I will have a go at rewording that bit

[@bradfooks4485]

@ 21:50 Simon says that 3 cells can't add up to 9 can anybody explain that for me

[@stevenape377]

Simon means that the cells cannot be 2,3,4, because that would break the rule that says all cells in a box that lie on the path must sum to a prime number.

[@bradfooks4485]

Ok box 2 can't equal 9. I think that was added to disambiguate the path and indicate which way to go

[@capush2]

Getting a little heavy on the ads

[@Pritchie45]

22 minutes

[@awilliams1701]

oh sorry that's a 4 by sudoku. ummmmm I know you caught that mistake right away, but seriously how do you not see that other 4? lol

[@katiekawaii]

With the difficult-to-see gray region dividing lines, the way-more-prominent purple maze walls, and the red line going right through the 4, I think it's an understandable oversight.

[@colinfun]

Given the instructions on the video, it is never made clear if the restrictions about the prime numbers applies to the mouse and cupcake squares or just the path between the 2 of them. So that clearly needs to be clarified.

[@Tahgtahv]

I would think 146 solvers as of the time of the video say otherwise. Why would you not include the start cell or end cell when considering pairs of cells?

[@colinfun]

@@Tahgtahv Because you can argue that it is NOT on the path since the path is only how he moves from point A to point B, not the end points. Think of it this way, you make a route to get TO your friends house, his house is not ON the route TO it, it simply marks the END of the path.

[@AG_247]

The rules say, Finkz must go the way and find the cupcake. If the path misses the start and the end cell, that means, Finkz has to teleport from its starting position to the second cell and walk from there just one cell short to the cupcake and teleport the final step again. Since teleporting hasn't been mentioned, I'd assume, Finkz also walks from its starting position until it can touch and eat the cupcake at its location.

[@colinfun]

@@Tahgtahv Also your logic doesn't make any sense Tahgtahv. Quoting how many people solved the puzzle as intended doesn't prove it is confusing instructions since you are only counting the people who were not confused. You would have to be able to prove that no one got the instructions the other way around in order to prove there is no way for the instructions to be confusing!

[@colinfun]

@@AG_247 I completely disagree with your assumption that it requires teleportation. Like I said in my first reply, if you make a route from your house to your friends house, that route doesn't include either houses they are simply the start and end point of your route, same principle here, the square he is in and the cupcake are simply the start and end points of the path and are not necessarily along the path.

[@eveengineer4147]

First :)

[@hrbattenfeld]

Kind