Two Truths And... Another Truth!

[@ChrisNeffshade]

ChinStrap here. Thanks again for another great solve :) While you are right that you could probably pencilmark everything and get something out of it, you definitely approached it the right way, thinking about high digits and where they live. So grateful for another feature and I am glad you enjoyed.

[@martysears]

Lovely to see Chinstrap getting a lot of appreciation over the last month or two. He is a solid setter with brilliant ideas and masterful decision making when it comes to the choice and positioning of clues

[@OddLittleShoppingBag]

“We hold these truths to be self-evident, that all men are created equal…” is from the Declaration of Independence originally. Dr. King did memorably quote that line during his “I Have a Dream” speech, along with several other passages, to illustrate the distance between the rhetoric of our country’s creation story and the reality of its implementation, and to encourage us to bring the two into harmony. Very appropriate to quote that speech, as Monday is MLK day here in the US, when we commemorate his memory and his message. However, the original is from a certain letter of grievance sent by those hoping to become the founders of my country to their distant rulers in what is today your country.

[@Kairamek]

"All men are created equal," said a slave owner. Jefferson let freedom ring, but didn't pick up the phone.

[@markp7262]

33:01 finish. There's one question that can answer many questions in this puzzle, once you have made some initial determinations: "Where do 7-8-9 go in this row/column/box?" Loved it!

[@PassionPopsicle]

Early bird may get the worm, but night owl gets CTC for bedtime. And what a lovely simple ruleset, looking forward to watching ❤

[@tabularasa0606]

I prefer puzzles over worms anyway.

[@Cthulhus_Mum]

This got recommended to me with *zero* views - I think the algorithm finally has me figured out 🤣🤣🤣

[@chocolateboy300]

Thanks for the birthday shoutout, Simon. I am turning 28, which is the secret if the grid was 7x7 and whose digits also satisfy a German Whisper. I have been leaving comments and times under every video I have completed on this channel. It is my hope to watch every video and beat every single puzzle that has been featured on this channel. When I started this, I felt myself getting better at puzzles, being able to see the geometry better, understanding more of niche secrets. About two months ago after playing some speed solving puzzles that Mark made a video on, I happened to turn off the conflict checker. It was rough speed solving, but I forgot to turn on the conflict checker for the next video. I was surprised that I didn't even realize I forgot it until near the end of the puzzle. Since then, I have played every puzzle with the conflict checker off. That felt like the most striking improvement to me. I look forward to all puzzles posted in the future and you can see me in the past working on the back catalogue. Thanks again!

[@HeadMed]

I just recently turned off conflict checker. It definitely makes me feel special when I can solve a puzzle without it, but it sure is annoying to think I finished a puzzle only to find out I put 2 8s in a row somewhere and have to start over, which is exactly what happened to me in this one!

[@Paolo_De_Leva]

Highly recommended by Marty Sears and Viking Prime = *cosmic class* Thank you Simon for featuring extraordinary puzzles every day 😏👍👍👍

[@carstenkruse8527]

I remember in a very early video, Simon giving hints to doing a sudoku. He said..."immediately when I get a number, I check the row and the column." An ideology I took to me. I guess that strategy has long been abandoned

[@windybeach2184]

To be fair, he does admit to being outraged by doing actual sudoku 😂

[@RichSmith77]

He probably said it about a sudoku puzzle. You know, one of those where if he didn't do sudoku he wouldn't be able to do anything, so is forced into doing sudoku. 😂

[@bertcielen8709]

He puts a 678 in r6c4 at 50:25, completely ignoring there is already a 7 in the column which would have meant it should be a 68 pair and thus would have placed a 9 in r2c4, and doesn't notice it until more than five minutes later when it is an important step in figuring out the rest of the puzzle. That 9 in box 2 would have solved the 29 pair in box 3 and placed the 2 in c3.

[@sakkikoyumikishi]

12:05: "That's 8 and 9" And it also tells us where the same digits go in row nine. We don't know which of the lines in boxes seven and nine is an index line, but we do know that whichever one it is doesn't contain an 8 or a 9, so the other one has to have both. The thermomether, now, surely can contain an 8 and a 9, but NOT close to its bulb. It follows that the thermometer is in box seven, with r9c2 being an 8 and r9c3 being a 9. If that were the index line instead of the thermometer, we couldn't put 8 and 9 anywhere in row nine (since they certainly can't go on or right next to the bulb of the line in box nine).

[@Dazreil]

I think a better way to think about index lines is just think of them as being a consecutive number line, but some of the digits have been swapped, so in the example the 3 has swapped places with the 1.

[@RichSmith77]

...a consecutive numbers line that starts with 1 ...

[@damsonrhea]

So it's a secret you know, but you rarely use - indexing lines always have an even number of indexing (not self-indexing) digits. The index in box nine had one self-indexing digit, which put it at five indexing digits, so you knew it had to have one more self-indexing digit. The indexing line in box eight didn't have an odd number, so you should have been looking to put another self-indexing digit in box nine. I don't think that resolves it, but it does strongly suggest where you should focus.

[@kenhaley4]

I think one fact that might have helped is this: On an index line, every cell either indexes itself or belongs to a pair of cells that index each other. Right?

[@patrickgass787]

Simon, you did wonderfully - this is one of those puzzles that keeps you on your toes throughout; and in fairness, ChinStrap is one of those setters who insists on using some amount of Sudoku in their Sudoku puzzles, which as we all know, is one of the most devious and unfair stunts a setter can pull. I hope you will forgive him 💚

[@martysears]

💜

[@KrisCadwell]

Ask your doctor if pencilmarking thermometers is right for you.

[@Cassiebsg2]

To me it helps to corner pencil mark the place in the line they are, so I don't have to keep counting them. Then I just pencil mark with the middles once I have reduced the possibilities... like it's either these 2 or self. Works for me. :)

[@dominicsymes9189]

​@@Cassiebsg2 Hey that's really clever! I constantly have to keep recounting them

[@dominicsymes9189]

Seriously good puzzle ChinStrap! You've been putting out such high quality puzzles with such beautiful aesthetics for a while now, and this was my favouruute so far! Thanks so much ❤

[@inspiringsand123]

Rules: 06:35 Let's Get Cracking: 09:19 What about this video's Top Tier Simarkisms?! The Secret: 3x (09:24, 09:26, 09:28) Three In the Corner: 2x (39:55, 54:10) And how about this video's Simarkisms?! Pencil Mark/mark: 11x (21:54, 29:51, 29:53, 42:20, 42:51, 44:32, 45:30, 46:22, 46:49, 47:50, 52:55) Ah: 9x (18:41, 22:50, 37:13, 37:13, 40:11, 43:33, 44:43, 48:51, 56:03) Sorry: 8x (13:08, 15:59, 16:10, 17:55, 18:50, 29:13, 33:49, 47:20) Hang On: 8x (15:02, 27:25, 33:18, 36:32, 36:48, 54:30, 57:17) By Sudoku: 6x (17:11, 24:42, 24:56, 28:38, 49:28, 49:31) Useless: 5x (04:27, 14:43, 38:24, 38:24, 43:19) Beautiful: 4x (00:28, 40:36, 58:46, 59:28) Extraordinary: 4x (00:20, 04:50, 05:48, 06:17) Weird: 4x (21:10, 22:57, 32:29, 58:31) Bother: 2x (40:43, 43:27) Clever: 2x (57:37, 57:41) Deadly Pattern: 2x (51:45, 51:56) Come on Simon: 2x (31:47, 32:54) In Fact: 2x (39:23, 53:29) Plonk: 2x (44:22, 44:39) What Does This Mean?: 2x (19:30, 19:59) Nature: 2x (15:41, 55:56) Good Grief: 1x (37:17) What on Earth: 1x (34:00) Goodness: 1x (28:15) The Answer is: 1x (22:17) Recalcitrant: 1x (32:34) I Have no Clue: 1x (35:21) Horrible Feeling: 1x (29:48) Lovely: 1x (39:16) Brilliant: 1x (57:49) Ridiculous: 1x (22:20) First Digit: 1x (08:25) Discombobulating: 1x (33:53) Surely: 1x (30:31) Puzzling: 1x (03:22) That's Huge: 1x (37:21) Cake!: 1x (04:35) Most popular number(>9), digit and colour this video: Seventy Eight (4 mentions) One (100 mentions) Red (6 mentions) Antithesis Battles: Even (7) - Odd (0) Higher (3) - Lower (0) Row (13) - Column (12) 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!

[@pokinDave]

I love that Simon has taught me enough Sudoku that I can now be frustrated when he isn't doing enough Sudoku in his Sudoku puzzles. I appreciate that too many pencil marks can just make clutter and not insight, but once you can get a cell to 3 options it is very helpful to note. I think he could have solved this much more smoothly if he just recorded more of the insights from his brilliant brain.

[@HeadMed]

If the 2 cell line is an index line it has to to be 2 then 1 otherwise it would be both an index line and a thermometer, which is against the rules

[@A_CC_K]

So happy that the Saturday puzzles will be continuing. Brilliant looking puzzle chinstrap.

[@jamese4336]

I got to a similar place at to you 38:40. The deduction I found that really helps is asking where do the 6, 7, 8, 9 go in row 6. That then helps you sort out most of the thermo in box 6 and starts cleaning up the puzzle very quickly.

[@vjay4297]

Today I feel like giving love ❤️

[@BijickY]

Appreciate it. ❤

[@chocolateboy300]

I finished in 86:56 minutes. Two truths and a lie puzzles are always so fun to do. This one was especially satisfying with the the way the geometry worked. I think my favorite parts were ruling out indexing from the r1c4 line and the limitation of 6789 in column 9. For the r1c4 line, there was a cool geometry detail which forces a 123 onto the beginning of the blue line below it. This simultaneously breaks both possibilities of the other red lines through a 2 in r4c3 and a 3 in r3c3. That blue line was so clutch and awesome to see. My other favorite part was the one that finally finished the puzzle and that was to ask where 78 went in column 9. However, in row 3 there also had to be a 78 in box 3. This forced the indexing on big blue and gave a wealth of information. Brilliant setting on making the geometry of the lines be so cool. Great Puzzle!

[@林老師-i5d]

40:45 for me nice puzzle

[@redridingwolf]

I love how Simon said he was not going to mark the thermo and then marked it to show why he wasn’t going to mark it.

[@KSilverlode]

I enjoyed that puzzle very much, and am pleased that it didn't take me much longer than Simon for once!

[@Xelopheris]

Classic Simon, diving too hard on only the variant rules, taking 5 minutes to solve what you get when you ask "Where does 9 go in row 9"

[@windybeach2184]

This was a very enjoyable puzzle! Indexing isn’t my strength either but I’m getting the hang of it and actually beat Simon’s time (rare)

[@davidlittlewood2860]

I spent a long time thinking it was one colour that was exclusively a thermo and the other two colours were indexes. 35:11 after I realised what the rules actually were! Adequate at sudoku, awful at reading.

[@RichSmith77]

I made the same mistake at the start. Did you get to an impossibility the same way I did? Line types in boxes 7 and 9 cannot both be index line types ➡️ all three of them must be thermos. In row 9, 789 can only go on the thermo in box 7. Now in row 9, 6 can only go in r9c7. That makes that thermo end 6789, with 7 in r8c7. All other lines must be index lines, including the one in box 6. That has to have 1-6 on it, so there's a 789 triple in column 7 of box 6 - and it's pointing at a 7 in r8! NO!! WHAT DID I DO WRONG!!! Oh, I misread the rules. Nevermind. Let me start over. 😂

[@Gonzalo_Garcia_]

11:48 for me. What a fantastic puzzle!! Really enjoyed this one!

[@Fahrenheit1407]

With the times you post every single video, you must really be a world class elite solver. Ever considered trying out the world sudoku championships?

[@ThePolymathlete]

Quick 30 minute puzzle for me

[@dontmindme2844]

I found this one really easy. Finished in 22:56

[@allendracabal0819]

I like how when Simon pooh-poohed fully pencil-marking a thermometer, he implicitly acknowledged that not doing so might make the solve take longer.

[@snjyjn]

Lovely puzzle, and great solve. 66:32 for me. However, I did pencil mark the whole thing :-). I do believe that Simon missed a trick with his initial discovery of 78 in box 3. At that point, it becomes clear the R1C9, and R2C9 must be from 678 only. That, and the logic around the fact that there are 7 digits on index lines in R3, the fact that leads to R3C9 becoming 78 as well. I think that would have helped Simon move along much faster (typically, I find that my solve times are about twice as long as Simons if I can get the logic right!).

[@ceevio_art]

32:23. First index line puzzle I've done, and once my resistant brain opened the door to their restrictions, the puzzle solved itself pretty quick. I admit it - I am an avid pencil marker and Goodliffe the heck out of any cell that has less than 9 possibilites. Sure, it gets pretty messy, but I can see quintuplets and sextuplets easily - and all the 123456 cells everywhere made the rest easy to fill in.

[@dontmindme2844]

Count me as part of Team Goodliffe. 22:56. I find it usually necessary for any puzzle involving thermos

[@MarkWiseTechno]

01:01:59 That was really enjoyable! A very nice balance between difficulty and interesting logic.

[@sigawof]

Finished in 31:12, missed some obvious things I could have filled in the index lines...

[@paula-zzz]

i enjoy my ctc time every night so much :)

[@bobbie0976]

The year of sudoku is starting off with some great puzzles!! Solved just over half of the video length!

[@EkuuleusNorth]

About an hour. Great puzzle

[@roba11en79]

Can someone please explain the break in? Why couldn’t 789 be in the top row of box 7? he didn’t explain and just said they have to be there

[@tessabrisac7423]

It 789 are together in the same box in row 7, either in box 7 or box 9. If you place them in box 7, making the line in this box the index line, and the line in box 9 a thermo, but 7, 8 and 9 would fall in the first cells of the thermo, which can’t work.

[@RichSmith77]

I'd say he spent a minute and a half explaining from 15:10. He didn't just say "they have to be there" without explanation. Was there a particular step in this explanation that you felt was a leap?

[@Cassiebsg2]

Sure. 9 can only be at the end of a termo. If the termo was in box 9, where would you place the 9 or the 8? They would be in the same row as in box 8, so that would not work. Thus Box 9 is index, and box 7 in the termo. Now you can place 9, 8 and 7 in row 9, since the index line moves from row 8 to 9.

[@ericpraline1302]

Not nearly as duplicitous as I was expecting. Very smooth, thanks. Though I do tend to pencil mark thermos I appreciated that this puzzle can be solved with very little marking.

[@Coyotek4]

28:29 ... a fun twist on the 'two truths and a lie' genre Nice puzzle!

[@stevieinselby]

Great puzzle, finished in 30 minutes 👍🏻 Simon's aversion to pencil marking definitely held him back here, from the moment he put 7/8 corner marks in box 3, the last 2 cells can be penciled in as 678. (I don't think putting 78 in the 6th cell was right, as 6 could be on the line in box 5).

[@stangerrits6712]

Indeed he could have done a bit better there with the pencil marking. Two of the three cells in box 3, row 9 had to be from 7 and 8. Simon also concluded that either the seventh or the eighth cell on the line needed to be from 1 to 6, because of the relationship with the shorter blue index line. Therefore the sixth cell must be 7 or 8, placing a 6 in either the seventh or the eighth cell.

[@e.m.b.5090]

Little corollary from the rules (really just a concretization of "no line can be ambiguously both"): No line can be just the digits 1 through n in order, since that is what a line fulfilling both conditions would be.

[@5AMA5]

Simon: To show you why I will not annote the thermo I will annote the thermo.

[@debrawilden1971]

For thermo lines, I put a circle at one end. For index lines I drew a line in the line, making it solid, but not sure why the blue lines were all solid. For blue line, I drew a green line on it to indicate index line.

[@piarittersporn]

Wonderful and very exciting puzzle.

[@noxumbra173]

At the 13 minute mark, the question to ask is where does 8 and 9 go in row 9? The only place is in box 7 if that line is a thermo.

[@grahamania]

00:39:38 for me. Great puzzle. I thought the index lines were very well used to limit the options. Kind comment.

[@Kleyguerth]

Too bad the non sudoku puzzles won't be regulars anymore, I was looking forward for one today to try out

[@whypick1_]

Done in 15:07 \m/ Spoiler Guard: Knew figuring out which line in the set is the thermo would be the key. Purple was easy, only one legal place to put a 9 on row 9, which made box 7's line the thermo. Determined box 6's line was blue's thermo because if it was an index then box 6 column 7 would be a 7,8,9 set...pointing right at R7C7's "789", which is a no-no. Determined red's thermo line by seeing that if the line in box 2 was an index line (therefore a 1,2 pair), the red bulb in box 5 would have to be an 8 or 9, which is not possible for either line type. Pretty simple once you do that, and I managed to not majorly screw up how Index Lines work for a change, making this a rather speedy solve.

[@codahighland]

Right off the bat at 13:00 I see that if box 9 was a thermometer then r8c9 must be 7, because if the line contained 123456 then it would be ambiguous whether it was an index line or a thermometer.

[@jirtarWorld]

If only you focus on high digit! Except one index line, they are all fill with low digits! And as always ... you neglected ===>>> doing SUDOKU in a SUDOKU puzzle!!! Simon you are a genuis ... but common, please ... do sudoku!!! (and pecil mark stuff ... box 4, if you pecil mark high digits 6789, you will discover a pair in column 3. As example) The high digits should flow if only you do sudoku on row 3. And, if you had chained with the index line in box 3 ... and get the 768 digits ... Another flaw you are use to ... do not revisite your pencil mark ... when you enter new stuff in the cell ... and check how it afect previous pencil mark ... You miss because of that, for example, the 1 aligning in row 4, which give you the one in box 6. Of course you always finish to find them one way or another ... but many time it will help you and speed you. 4 pencil mark in a cell it is [very] acceptable. (can often help spotting stuff ...) 5 if deseperate ... 3 very good ... 2 the best. I agree with you, thermo pencil mark not very useful ... but something they help spoting some strange interaction ... Like in this puzzle, the fact the thermo cannot be max, because the cell with "789" in box 9 cannot be fill, can reduce the pencil mark for the thermo. Thermo are my less favorite rules they are rarely useful ... expectially when the are short, or very short. I waste time ignoring the "thermo" (lenght 2) [at first didn't know it was a thermo....] because ... too short ... and it was the one to look at! (at some point) Great job anyway ... you are far, far ... far better than me ... but if feel very strange when i spot thing you don't (before me) (mainly because you refuse to do sudoku most of the time) I think your approch is better ... because finding the logic of the puzzle is what make it possible to solve it ... But since i am often stuck i fall back to sudoku as often as possible in the hope it will help me...

[@MorganBlackthorn]

Wonderful puzzle! I love index lines ❤️ but I think that either they're just not made for Simon or he just needs more practice with them, because he tends not to spot a lot of deductions tied to them... Oh well one can't be absolutely brilliant in EVERYTHING, right? It should be already illegal how many things he can spot in a puzzle which would be 100% obscure to me.

[@stangerrits6712]

At 12:47, if the line in box 9 would be a thermometer, it couldn't be ending in a 6 right? Since it's a six-cell thermometer, it would then read 1-2-3-4-5-6, but that's also a valid indexing line (with all positions indexing themselves). If I understand the rules correctly, that's not allowed.

[@tBagley43]

43:07 very fun puzzle

[@tessabrisac7423]

Very surprised I could solve it on my own and in about an hour, making it fairly approachable given my stable “dinosaur” level. And brillantly fun!

[@conaluk7662]

Nothing means more to me than the beef Simon has with Marks pencil marking

[@LednacekZ]

28:48 for me. quite easy to figure out the index/temp lines.

[@snowfloofcathug]

24:09 he makes a really clever deduction that those four digits must be four of the five on the other line, but doesn’t that mean the lowest 78 is *guaranteed* to be 78 or else they’d take up too many of the five squares? And since they’re on index 6 we now know the top two must be 678?

[@phuybrechts6875]

Pencil mark those indexlines , Simon . They reveal more than you think 🙃 ! Par exemple: box 8 😅

[@toddbiesel4288]

It appears that the rule that a line could not be both index and thermo was not used in this puzzle.

[@thebishop4112]

Yes, on first reading of the rules, I was sure that this would be necessary to disambiguate further down the track. It does seem a rather strange thing to articulate as the only way it could come about would be an entirely self-referencing index line beginning at 1. Perhaps it is a hangover from another puzzle with the same ruleset.

[@michaelpdawson]

I was sure at the beginning that it would be necessary to apply this rule to the 2-cell line to disambiguate. But then Simon determined that that line was a thermo and destroyed that guess!

[@Frank_Alias_Frank]

At least the rule tells you, that you can never put 6 on the tip of a thermo of length 6, but that deduction wasn't the most helpful thing in this puzzle. But it is worth thinking about it.

[@srwapo]

24:24 after I broke the puzzle, looked at the rules again, and saw I was doing 2 thermos, 1 index. 🤦‍♂️ Restarted my timer for my second attempt, guess I had a very little bit of knowledge about the bottom row on my second attempt, but everything after that was different.

[@Tsunami14]

I'm a programmer, and yet the definition of index lines still breaks my brain. The only way I can deal with them is to "cheat" and recognize the final pattern that emerges from the rule. That is... by default, the digits on the line will sequence upwards from 1, but any pair of digits are able to swap positions exclusively.

[@twocflyer7520]

21:50 Mark = would pencil mark this thermo; Pencil Marking this thermo = Ludacris; therefore … Mark = Ludacris 🤣. Simon said it, not me!!

[@KamiInu666]

A rare day when my time is significantly faster than Simon (or Mark) - I got 16:07 for this one

[@sammycooly1709]

7:45, I know you’re a busy man Simon, between the channel and the kids, but I genuinely think you should try learning some programming. I know it may not be in your interests, but I genuinely think you would be very good at it, as someone who can think in puzzles and predicts the behaviour of numbers. I’m not saying this as someone looking into programming from the outside either, I’m someone who can code in 4 languages at the moment, and the kind of logical thinking that it requires feels very similar to what you use to solve these puzzles!

[@przemekmajewski1]

smooth 45 mins solve here :D much fun

[@malvoliosf]

Simon, a Brit, can quote the “I Have a Dream” speech - but not the Declaration of Independence.

[@RichSmith77]

Are you sure it got delivered? Was it recorded delivery?

[@wadehines9971]

Took me almost 2 hours and well over a pint of whiskey, but was half way through the whiskey before I started. Strange.

[@yashmehta9299]

Got it in 40:20!

[@darreljones8645]

I'm a little disappointed that the rule that "no line can be ambiguously both (a thermo and an index line)" never came into play. For what it's worth, that's only possible if the line looks something like 1-2-3-4-5.

[@PathOfShrines]

Cool puzzle. 23:41 for me.

[@HippoNird]

00:40:01

[@damsonrhea]

He needs to be asking about where the 89 goes in row nine. As soon as he got them in row eight, that should have been the next question.

[@BrianOsman]

Exactly. Actually, just asking where 9 goes in that row immediately lets you know how to disambiguate the purples.

[@damsonrhea]

@@BrianOsman Yeah. He said it himself - you can't put a number higher than the index length on an index line. It immediately tells you which is which.

[@TurquoizeGoldscraper]

55:01 for me.

[@Arci13ful]

My time: 02:14:25

[@minhluu7886]

38:41 Not a fan of index line puzzle so just brute pencilmarking the whole thing

[@Ardalambdion]

Who thinks about thermometers, who thinks about indexing lines and who thinks about something else when looking at this picture?

[@sivsuikki9428]

Not smart enough. Just gonna listen and learn.

[@77relbot]

index lines are horrible

[@C0nrady]

This puzzle completely frustrated me with Simon's solve. We seemed to have massive leaps of logic. He explains the most basic bits that anyone watching this channel will know as its in every puzzle (also very annoying now as its in every puzzle), but then misses something that may make sense to him but it's leaving us behind. Well me anyway. This is late for me but deducted a line is s thermo therefore other lines index, how, just how?

[@thebishop4112]

I understand your frustration, but I think you need to understand that not everyone watching this video have watched all of Simon's other videos. In fact, some people watching this may be very new to Sudoku, and so I don't mind at all that each step is explained carefully. Personally I find Simon's manner to be so delightfully charming that I don't mind at all being told things I already know (I am still delighted when Simon shares 'the secret' even though I've watched hundreds of these videos), but if that is not for you, I could suggest you watch the solve at 1.5 or 1.75 speed, or simply fast forward the bits of logic that you find straightforward. In terms of skipping some bits of logic, I find that Simon rarely does that, but he is human after all, and solving in real time. I find if I don't understand something, chances are it will be addressed somewhere in the comments section of each puzzle, or you would be most welcome to ask. It really is a lovely community here. With best wishes.

[@renedekker9806]

Because that is what the rules say. Of each colour, only one line is a thermo. Once you have identified that one, the other 2 must be index lines.