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This is the former home of Thomas Snyder's puzzle blog "The Art of Puzzles" from 2007-2012. For the latest and greatest puzzles including sudoku and other abstract logic challenges, please visit Grandmaster Puzzles.

art of sudoku

The Snyder Test?

So I've been playing around with GPT-4 and some of my own training data (writings, puzzle images, videos, things like that). After some very careful prompting (asking it to write an email and use whatever associated media it could to prove to a friend it was me), my mind is blown away by the result. It just sent back one web link, a google doc that it somehow posted from my own account!!!
art of sudoku

WPC Playoops

So a tremendous WPC has ended. I simply wish my performance in the end lived up to my own expectations in the way that the quality of the puzzles and organization certainly did. Many thanks to both the Chinese and Hungarian teams for working together to make a harmonious, and truly international, championship. The Yin-Yang logo was quite fitting.

While I am proud to again be part of the same podium of finishers from the last three championships, and of course proud to have been part of a very successful US team completing its 14th world title, there is something quite crushing in how the last few minutes of my championship went. I found myself at the final desk of a playoff round, having earned by good performance over a minute lead on my German rival Ulrich, and I let it all slip away.

The playoffs started with my teammate Palmer Mebane having a large lead on the field -- about five minutes over second through fourth where Ulrich Voigt, Hideaki Jo, and I sat, but only 21 seconds between the three of us -- as we entered a semifinal that this year would eliminate 10 solvers down to 2. As I sat and watched Palmer race through the first couple puzzles while the clocked ticked up to 5 minutes, I knew this would be a sprint to the finish with just one spot for the three of us as Palmer's seemed very safe. On the first puzzle, a Bosnian Snake, I bested both Ulrich and Hideaki by about a half minute and was immediately into the second spot with the narrowest of leads. This widened as I systematically attacked and conquered each of the next puzzles -- a Word/Nurikabe variation, a Pentomino variation, a large and oddly shaped Slalom puzzle, .... I always held onto the second place desk, and slowly the margin went from about 15 seconds to what seemed at least a minute. By the sixth or seventh puzzle in the race, Hideaki must have lost a few steps as it was suddenly just Ulrich close at my heels. I was most worried of puzzle 9, a new puzzle style that had not been present in the championships nor that I'd ever really solved before, and seemed most likely to potentially trip me up. But I managed that well enough and found myself at the final desk as Ulrich was still working on it. With me starting 10 before he had turned in 9, I had over a minute edge and just needed to hold serve on what should have been easy for me -- a number placement style. But it too had not been in the championships and I had somehow forgotten some of the important meta-strategies of thinking that would get me started quicker. I was a bit slow to see the first few moves, but was quite anxious for all the numbers to arrive. This impatience is maybe my biggest puzzle weakness at this time as it can lead to really bad decisions. I've recognized it before -- and even a week or so ago with the only LMI tests I've done this year -- but everything seemed to go wrong here and suddenly. In this case, with ~12-15 numbers to go and the feeling Ulrich might be close to the end too, I used quick placements without a sure check of the constraints to put the last numbers in. And while I checked that I formed locally valid groups, I failed to consider the rows or columns before I raised my hand to turn in. And two seconds after the hand went up, but while I could still see my grid, I observed that a minute (lifetime?) of pain was awaiting me. I was obviously wrong (but somewhat easily fixed) but had to serve out penalty time. And Ulrich turned in before I could make any correction and that was that. Wide right. No goal. Renban Words. Things we will not speak of again.

Not since I lost the 2009 Philadelphia Sudoku tournament by a digit transposition error and turning in too early (with what would prove to be over 4 minutes I could have checked after destroying the puzzle itself) have I felt that I was the sole reason for my defeat and that is what is most unsatisfying. Maybe I'll never learn particular lessons from the past. But maybe I'd not be in these situations if I hadn't walked the risk-reward line of a logical to intuitive puzzle style in the last few years to become as fast as I am. I know over time I will come to accept how great my 3rd place performance was, as how many can be a podium finisher at a world tournament, but for now there is mostly disappointment. I'm left with a lot of what ifs, and the long flights home are never comforting when the questions are so numerous.

Added onto my own loss was that after not making it into the finals, I had to watch my teammate Palmer Mebane hit his own wall of performance against Ulrich and lose in the five puzzle finals to deny the US another individual title.

But I am leaving the competition with a different kind of joy, unrelated to how fast I can solve a puzzle. I was delighted to hear the thanks from the community for non-competitive things I have been doing in puzzles like my Grandmaster Puzzles site. The Around the World in 80 Puzzles rounds seemed to be well received and I achieved a goal of writing puzzles for the WPC now. My favorite moment was the unexpected news that some of the puzzles I had written for one nation's team had helped them gain team sponsorship which, with the current WSC/WPC makeup, is quite difficult. Having my small efforts pay off in such large ways is rare so I am glad to have helped. It has been obvious for awhile that I may be well past an inflection point in my life where competition interest diminishes for puzzle creation and other roles instead. I at least feel more consistently successful in the latter, and the rewards are ones that are shared with others which makes them even sweeter.
art of sudoku

WPC Update

I'll limit myself to about 250 words.

First day is done, and team USA got off to a quick start in the first team round with the fastest solve (in 28 minutes), next fastest in 35. It was a well-designed round, both for having interesting puzzles but also because it actually ran for 60 minutes and many teams got a chance to fully experience the "Welcome to China". More team rounds should be like this! I worry about the opposite kind of result with tomorrow's massive snake round.

My first day has been average, with issues of timing (for example, being stuck with just half dominoes and taking almost 10 minutes to earn 0 points when I could have finished the classics round if I could just be (a) luckier or (b) more meticulous in learning the logic of these things) and also mistakes. My best round was the last, round 7, the Serbian designed round, where I almost finished the full set in time and expect 113/120 points before normalization as just the doubled skyscrapers eluded me in the last 6 minutes of time. I expect the day's results to have me in the playoffs but not in the top 3 at the moment.

The runaway leader of the tournament so far is Palmer who has had very steady and good rounds, even with at least one large point mistake in round 3 of 70 he could have had. At midday he was in the 900s with a large group from 2nd to 10th all in the 700s. I hope the US can continue its strong showing in many ways as the second day approaches.

As for the Around the World in 80 Puzzles concept, where I became an author with Team USA for the first time at the WPC (with other teams from Netherlands, India, and Serbia also writing 20 puzzle/60 minute rounds): I found the other 3 rounds very enjoyable with the different teams taking different approaches to the design, kinds of puzzles, and hidden themes and such. Our round, the "Doubled Decathlon" had standard puzzles and doubled variations (like a Yajilin that goes from 1x1 black squares to 1x2 black dominoes). And while the rules were doubled in some ways, we did our best to try to double the puzzle set-ups too in clever ways. I am glad that the Around the World in 80 Puzzles concept came together well under the direction of the Hungarian organizers and the incredible work of the international puzzle makers.

So an interesting tournament, and more interesting puzzles to come tomorrow. That's much more than 250 words, but I'm horrible at counting puzzles. Off to bed.
art of sudoku

USPC Preview

After 9 straight years of competing (and 6 titles), this is my first year constructing for the USPC with 4 contributions from me. As such, I will hold off on much further comment until after the test. Best of luck and skill to the competitors vying for a spot on the US team. I think this year could be a wide-open race for the two positions.
art of sudoku

Puzzle and Life Update

This week (yes, week!) is the LMI Marathon Puzzle Test. 12 different authors have put forward bigger than usual challenges meant to be solved one at a time. I've contributed a Star Battle puzzle there, which I hope you enjoy.

Grandmaster Puzzles, my new puzzle publishing site, passed 50 puzzle prescriptions this week. If you haven't started to go there for my puzzles, what are you waiting for? Please update your links too.

I'm 74% settled in the Seattle area now, with all furniture in place and boxes slowly getting unpacked. It has been a lot of work, particularly in the middle of everything else I'm doing. Some of you may be wondering why I'd launch a large puzzle project just before moving instead of after. Well, that gets to the last bit of news.

I'm finally in TIME Magazine. Sure, I made the website before with a Philly Sudoku video story in the year of Eugune, but print for TIME is what most people will call "real". The US Team's experiences at the most recent WPC in Croatia were written up by Lev Grossman for TIME, and we've been waiting for the article for months. It looked likely at the end of December or early January (except for the Person of the Year issue) so I got my new project online as soon as I could at the high quality I wanted it to be at launch. But magazines take time, and I ended up getting 52 puzzles out before the article finally appeared. Of course I had other deadlines besides TIME, but I want to grow an audience of puzzle solvers and there are only so many ways to get free publicity these days.
art of sudoku

A new gift to Corral Fans: "Rubber Bands"

I've spent at least a dozen hours in the past month arguing with people on "Corral" vs. "Cave" puzzles. It's caused a lot of stress, almost lost me one collaborator, and it continues to haunt me as others are sharing my puzzles in new settings and reviving old arguments.

I feel it is now some sort of dogmatically argued issue where there just will be no agreement between the two sides. Sure, mathematically the puzzle definitions are isomorphic, but Corral (originally "Bag" until renamed for the 2002 US Qualifying Test) is a loop puzzle, and Cave is a shading puzzle. The two just can't coexist in any solver's mind. I've found I clearly solve it as a shading style, with identical notation to most other shading styles, and therefore professionally I have chosen "Cave" as the name I use for this genre. No loops needed.

But, if "Cave" is controversial to you, we can reengage in the flame-war over here if you want. Instead I wanted to offer a gift to you, Corral fans. It seems you loopers just see the world differently. So I wanted to repackage my favorite shading puzzle style for you to better enjoy. It's a style I dare not name as you probably don't like it at all and I don't want to sour your new impression by bringing up memories of fully darkening cells or anything. But with an open mind searching for loops, I'm sure you'll love the new twist. It is a style I call "Rubber Bands."

Rules: Stretch some rubber bands over the posts in the grid, reaching vertically or horizontally only between posts. Each rubber band will surround exactly one given number, and each number in the grid will be surrounded by exactly one rubber band. The number indicates how many unit cells that rubber band surrounds. Rubber bands can touch at a post, but cannot share an edge and cannot overlap to both contain any square. Rubber bands cannot cross themselves. All internal (black) posts must either touch a rubber band or be inside a rubber band. Cells outside the rubber bands must form a single contiguous group.

I find it particularly challenging to solve Rubber Bands by just drawing the edges, but I also find particularly challenging puzzles to be very fun. So I hope you give this new style a try and solve it as the instructions intend. The new "internal post" rule is so much better than that 2x2 shaded square nonsense anyway. At least if you are being loopy.
art of sudoku

Trapped in The Maze of Games! Help!!!

Yesterday marked the start of an exciting Kickstarter campaign from my friend and PuzzleCraft co-author Mike Selinker.

The campaign is for The Maze of Games, a quite unusual book that is kind of like a choose your own adventure and kind of like The Fool's Errand all under one cover. I've gotten a sneak peek of the current draft and it looks to be a really incredible experience for all puzzle lovers. A truly one-of-a-kind book.

And the early Kickstarter returns have been astonishing. None of us had 4 hour and 48 minutes in the pool for how long the project would take to get funded. This doesn't mean you've missed your chance to get the book. But it does mean you now have a new responsibility to help out with The Conundrucopia, a companion project set-up for the book.

You see, sometime last month I was signing a bunch of contracts and must have missed a special provision from Mike that I be "locked in a cage" until the internet had contributed enough money to free me. But this is indeed the case. And he got a lot of other puzzlemakers too. We've each agreed to contribute a unique puzzle for The Conundrucopia, but only if enough money is raised will each puzzlemaker -- and their puzzle -- see the light of day.

I'd certainly like my puzzle to be released. In the words of Mike: "You hear that Internet? Thomas would like to get out of the cage". Reserve your copy of the Maze of Games, and support The Conundrucopia at the same time! I, and my fellow puzzlemakers, would really appreciate it!
art of sudoku

Dr. Sudoku Life Update

I had a post I wanted to make after Mystery Hunt, and it was not the last one that is now at 350 comments.

As I told almost all the friends and teammates I met last weekend, my job at a biotech start-up has ended. I am soon to be performing a "soft reset" of my life by moving to Seattle in February and doing other things for awhile. Certainly, my new puzzle project Grandmaster Puzzles is one of these things, but so is running a marathon again, sleeping again, enjoying life again. The end of my 32nd year was the worst I've known. The beginning of my 33rd has been great and I hope it continues this way.
art of sudoku

Too Big to Solve?

Not my tagline, but a good description for the Mystery Hunt that just happened. One line of dialogue after last year's Hunt that I led with in my wrap-up was a question of when is too soon for a Hunt to end. I said, in this era of a few competitive teams trying to grow to get over the winning hurdle, constructors aiming bigger was a mistake. The Hunt ending after 36 hours (Midnight Saturday) is fine if that makes the solving experience stretch over the weekend for everyone else. I won't comment generally on this year's effort but it seems a great example to point back to of too much ambition by too many people towards the further militarization of the size of Hunt so that by 2025 the team "The whole of new USA" can go after the coin against "USSReunited" for at least a month. The sense of "puzzle" versus "grindy work" is also a discussion I have every year and I don't choose to repeat myself. I've felt since 2008 that the Mystery Hunt is far from an event I'd regularly attend in person although I'm glad to have finally been onsite to play with Team Luck with whom I've been a "free agent" now for three years.

I had a good solving year as things go relatively, but it was mostly demoralizing personally. I soloed Palmer's Portals, for example, but spent many hours after basically solving 8/10ths with a need to tweak a very small and underconstrained set of things to get from that hard work state to a finished state. At some stage I told the team "I'm going to solve Portals and the Feynman meta and then go sleep" and I met this goal but in many times the expected time when I gave the statement. I led the solve of both Danny Ocean (with zebraboy stating the most necessary last bit to get my work over the cliff) and Richard Feynman (with Jasters). I obviously co-solved lots of the logic puzzles and other puzzles, and gave various finishing help to a range of things too. I think I did this best for "Kid Crossword" once when he had spent a lot of timing mastering the hard steps of a crossword/scrabble puzzle -- and could quite impressively fast rewrite out the set of steps I wanted him to do about the puzzle -- and the follow-up steps were not obvious but I led the killing of the beast. This was too often the feel for these puzzles, and my assassination rate was far lower than I wanted. My Sunday was spent earning 3 puzzle answers by actually going to an event, and then falsely believing the power to buy some answers would let me finish solving the Indiana Jones mini-metas -- where I had already mostly soloed Adventure 2's snakes with 5/8 answers, but then killed myself dead on #1/Ouroboros for the rest of the day for so long solving, as many solvers will say in hindsight, the puzzle that was meant to be in one of a dozen ways and not the puzzle it was. Let me state here as I did for hours with my team, the phrase "I'm not cut out for this" is horrible flavor. It implies both cut this out and, in a different way, also don't cut this out. This makes you want to cut it out, which takes a lot of time, but also to not invest too much time in cutting it out, so as to save the wasted time of doing a task you are being told not to do. Other wordings are far safer, and implied negatives within positives is one of the five worst flavor failure modes in my opinion. Puzzle editing and flavor text is an art and is certainly the biggest variable from year to year and constructing team to constructing team.

So yeah, Mystery Hunt happened. And there were the usual share of overwhelmingly incredible Aha moments. Endgame seemed very fun and I wish all teams could do just that for the weekend or at least a lot more things like that. More of that, and more sleep, would have both been some good choices this year. If only the puzzles solved on schedule.

ETA: And as I added far below around comment #300, as a solver who was both frustrated yet had fun in this Hunt, I do want to thank everyone on Sages for the incredible effort they put in. Making a Mystery Hunt is a gift for all solvers whether it matches expectations or not, and as a mostly thankless job I do want the constructors and editors and software engineers and graphic designers and cooks and phone center workers and everyone else to know I appreciated all you did over the last weekend to give us several days together for puzzling.

Further, as I was asked to write a larger piece elsewhere that has given me personally a lot more attention as the face of the criticism, and as I use the phrase "My team" a lot in general as solving forms this kind of bond, I want to be very clear: since Bombers broke up after 2009 I have been a free agent. I have solved recently with Team Luck but am not a core part of their leadership and these opinions I state are my own. I intend to form my own team next year to go after the coin again, and if you have a problem with what I have said anywhere on the internets, please hate me for it. I believe in my posts I have been offering constructive criticism, but even what I have said is without all the facts of what went on inside Sages so I could easily be speaking from ignorance a lot of the time.

EFTA: Thanks to tablesaw for pointing out this chronologic feature of posts. If you want to see all the additions to this post in time sorted order, go here We're on page 14 at the moment.