What Else can a Thermometer Show You?

Normal sudoku rules apply. All Thermos are also Region Sum Lines. Digits along a blue line must strictly increase from the bulb to the tip and must have equal sums for each box the line passes through.

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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 championship 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

[riffclown]

Wow! Wonderful surprise. Great Solve. Thank You so much for taking a look at this one.

[koosvanamerongen]

Turns out thermos and region sum lines combine nicely. I realized that in case a thermo of length five passes through exactly two boxes, it holds that the first digit must be at least four. Reasoning: the fourth digit is at least 2 bigger than the second digit and the fifth digit is at least 2 bigger than the third, and the first digit must cover the difference. Note that a thermo of length five that passes through exactly two boxes, will always have two digits in the first box and three in the second.

[markp]

15:24 finish. The easiest way to look at the 5-cell thermos is to look at the 2nd and 3rd vs the 4th and 5th (ignoring the bulb). Since the 4th has to be at least 2 more than the 2nd, and the 5th has to be at least 2 more than the 3rd, that means that the bulb needs to be at least 4 to make the equal sums. If the bulb is 5, however, it would have to be 5-6-7 to 8-9 (which is total 18 vs 17). Therefore, the bulb has to be 4, and the rest of the thermo has to be consecutive (either 5-6-7-8 or 6-7-8-9).

Of course, with all of the next level logic I found on the thermos, I completely missed the 7-8-9 triplet running through row 5 for a minute or two. Par for the course. Another excellent puzzle combining different rulesets!

[tinakerr]

26:44 but that included going out to fetch in the post, then getting up again to let the dogs outside and letting them back inside 3 minutes later because it was raining. I love the neatness of having 2 rules on one set of lines.

[emptyset]

Very neat puzzle. 39:35 for me. My rule of thumb lately is to attempt puzzles with video times under half an hour, because a relative noob like me has a chance to actually get through those ones.
A cool thing about this puzzle was that a fair bit into the solve I began to understand and use things which were available from the very beginning, without depending on other clues in the solution path - yet, I was still able to make progress and whittle away at the puzzle before coming to understand the intricacies. Made for a very entertaining solve.

[nidoking]

I started with the five-cell thermos on the right after putting 123 on the longest thermo. I worked out that the only possible values for those were 45678 or 46789, so they both definitely started with 4. Then I looked at the bent thermo at the bottom. With 1 ruled out, the tip needed to be at least 5, creating a 56789 quintuple in the column with the numbers already forced onto the thermo. That fills the empty cells with 123, and only 2 or 3 can be in the bottom cell. That rules 5 out of the tip, because it can't be a 235 run anymore, so the tip can only be 9, and both of the five-cell thermos are fixed.

[RockyInSea]

12:58 for me. I think the key was the 5 cell thermos. You need to look at the middle cell. Mark started the logic by ruling out 3 and 4, but then took a while to rule out the 5. A 5 in the middle would make the max below 12 (3-4-5) and 13 above (6-7). So now you know the minimum value is 6, but thermo rules makes the maximum 7. If the value is 7, then the "top" becomes 17 (8-9), and below the 7 must add to 10 which must be 4-6. If the middle value is 6, then the max "below" is 15 (4-5-6) and the minimum above is also 15 (7-8). So the only 2 values for both 5 cell thermos from the beginning is (4-5-6-7-8) or (4-6-7-8-9).

[realtylerdb]

22:18 - What a clever ruleset! Took me a while to fully wrap my head around it, but once it clicked it was phenomenal! Thank you Riffclown for a brilliant puzzle!

[mileswheeler]

19:44 for me. My first time beating Mark's time. I'm stoked!!

[ShinyBobblehead]

41:05 for me, spent far too long not realizing I hadn't ruled out the 7 at the end of the bottom left thermo. Once I spotted that oversight and got the center 7 it was steady hammering away and a lot of fun to solve!

[BrooksMoses]

16:06. Quite an interesting combination, and a lot of fun. And I was faster than Mark, too, which is nice (and unusual for me).

[AndreAy]

45:46 Solved it without any help from the video. Nice idea!

[nickatty]

I admit to a sort of cheat - I couldn't work out those thermo/sums in my head, so did a tiny bit of programming. After that, it all came apart quite nicely. I'm not sure if that's any worse than having memorised the options for killer cages from someone else's calculations years ago.

[Coyotek]

16:44 ... I loved the double-duty that these clues provided

Nice puzzle!

[wanderlustwarrior]

19:39 for me. That was fun, especially finding the hidden sets.

[warren_r]

This one took me 45 minutes, but almost two thirds of the puzzle came together in the last 6-7 minutes. I like this one a lot.

[stevepinard]

Very cool puzzle. 19:47 for me, and quite possibly the first time "beating" Mark's time (of course I was not explaining the solve).
Mark was so close to figuring out those 5-cell thermos. It's easy to work out that the last two digits must be [7][8] or [8][9] (Mark deduced correctly that [7][9] cannot work). There is only one way to make the first three digits add up to those region sums, and the bulb must always be 4.
(4) [5] [6] [7] [8]
(4) [6] [7] [8] [9]

[bristolrovers]

Riffclown, it's got to be a good, like the rule set

[mudscuffer]

18:45 for me. Nice puzzle. Felt pretty smooth.

[victorfinberg]

medium-length thermometers: GOODLIFFE THEM !!

did I mention ... ONE given