Hi all,

I hope you are enjoying the Thirteen Days of Tango. We’re certainly seeing more solves on the site compared to our Ready Layer One or Twelve Days of Sudoku offerings which were more experimental and/or unexpectedly difficult (as narrow path Sudoku can indeed be tricky compared to usual offerings). We’ll find some other way to re-post those works next Christmas season to maybe get more activity around them.

Today I wanted to share more puzzle design history info on Tango. We’ll have a proper puzzle rules and info page in the sidebar for Tango eventually, but for now …. The style grew out of our work with LinkedIn, as we wanted to explore potential new games after the launch of Queens (1-star Star Battle variation with hand-crafted grids). The broader LinkedIn(+me) brainstorming team raised different ideas and in the list were Binary/Binairo type games. I try to score each idea on approachability, depth, and uniqueness in different ways. While Binary-style puzzles have a mostly approachable rule set because everyone knows Tic-Tac-Toe and the solver just has to forget diagonals like they do when the name Queens confuses them, the genre is very low on my list with fairly limited logic and only computer-design needed (i.e., I have no idea how to make an interesting Binary puzzle with those rules). In particular the style is plagued by one of the worst rules in somewhat common logic puzzles: the “no two rows / columns can be identical” is a negative rule that may make a puzzle unique but it is far from a positive rule that opens up amazing new modes of thinking. I’ve never met a good negative rule, and it had to go as we considered positive replacements. With the agreement we would never mention that rule again, I played with other constraints that might glue a puzzle style together as it did need some multi-row/column connections to be both unique and moderately difficult. I played with regions (any even size box allowed for a drawn region shape, with very good deduction properties and unexpected complexities that I still like), colors/ciphers for fog-of-war-like properties, and edge clues (very good as glue with a few new deductions and visual design possibilities too). The edge clues moved all scores for approachability, depth, and uniqueness to a place the team thought we had something to launch. So collectively with LinkedIn, we evolved ideas from prior puzzle styles into a new game called Tango. LinkedIn’s goals focus more on shorter daily experiences, so some of the harder puzzles and larger puzzles were released back to me to use, as with the 8×8 puzzles in this Thirteen Days of Tango series.

Before you ask, I was not behind the naming of this game nor Queens nor anything else. Very important and highly paid people do that, like the ones who think most drugs should have J’s and Q’s and X’s and Z’s in their names. But I will say the “It Take Two to …” connection is super cool even though they don’t hit enough people on the head with it. And having a NATO alphabet letter for a puzzle I write has other benefits. Now to debut an ALPHA of FOXTROT in NOVEMBER while staying in QUEBEC.

And to keep this post mostly innocuous but reassure people, I wanted to share a Seattle photo as I was taking a walk because …

… I’d promised myself to treat myself and visit a nearby tower …

(more…)

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or solve online (using our beta test of Penpa-Edit tools)

Theme: The Eight Tees

Author/Opus: This is the 551st puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Fill each cell with an X or O so that (A) no vertical or horizontal group of three adjacent cells contains the same symbol in all cells (i.e., no XXX or OOO) and (B) each row and column contains an equal number of each symbol. Cells separated by an equals sign (=) must contain the same symbol. Cells separated by a cross (×) must contain different symbols.

Solution: PDF and selected animation.

Note: Follow this link for other Number Placement puzzles.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Thirteen Days of Tango Discussion post on the GMPuzzles Discord.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Open Middle

Author/Opus: This is the 550th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Fill each cell with an X or O so that (A) no vertical or horizontal group of three adjacent cells contains the same symbol in all cells (i.e., no XXX or OOO) and (B) each row and column contains an equal number of each symbol. Cells separated by an equals sign (=) must contain the same symbol. Cells separated by a cross (×) must contain different symbols.

Solution: PDF and selected animation.

Note: Follow this link for other Number Placement puzzles.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Thirteen Days of Tango Discussion post on the GMPuzzles Discord.

I used to blog. Then I stopped that to have a more professional-looking puzzle site with lots of authors. My brain didn’t stop having the thoughts I would have blogged. They got put elsewhere or shot off into the void.

I rarely use social media, and almost never now, particularly as the truth is up for consensus decree. I wonder if the world can look not round in those cool RayBans.

But still, I hear there are some doggies that are looking to make the world better through e-fishin’-c. Here are some ideas if a doggie comes up to you:

1. Make mental health care available across state lines without conditions or at least allow for “vacations”. Seriously, if I travel out of state A, I cannot speak to my therapist or psychiatrist from state A unless they are licensed in the state B that I am now physically present in. I’ll accept that I shouldn’t have the right to purchase firearms because I’ve been hospitalized for being bipolar if you’ll accept that my relationships with my doctors and therapists are the most important in my wellness circle and your laws are in the way of my best care and living a normal 21st century life.

2. Stop sending credit card account requests to my dead mother. It’s been 7 years, she is not looking for a higher credit limit at the moment, and it just frustrates my dad. She stopped voting over 8 years ago, and maybe that should matter in who gets the credit opportunities from the bank. I’d raise a request about junk calls too, but the people who set up the companies that make junk calls probably died years ago and it is all AI now. RIP MJ.

That’s all for now, just wanted to share some pleasant thoughts to the 3 people who still read this space. I am doing fine, have refilled my prescriptions with my doctor in one of the two states I go to while preparing for alternate care if I’m not in the first state I live in as much in 2025. In other words, still vertical when I shouldn’t be, and reacting to a song on repeat with great lines about college earning “the big D” and “would you like us to assign someone to worry your mother?”. I should be horizontal now.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Stripes

Author/Opus: This is the 549th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Fill each cell with an X or O so that (A) no vertical or horizontal group of three adjacent cells contains the same symbol in all cells (i.e., no XXX or OOO) and (B) each row and column contains an equal number of each symbol. Cells separated by an equals sign (=) must contain the same symbol. Cells separated by a cross (×) must contain different symbols.

Solution: PDF and selected animation.

Note: Follow this link for other Number Placement puzzles.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Thirteen Days of Tango Discussion post on the GMPuzzles Discord.

Since people keep asking, I’m doing fine. We’re planning for a change near the top, but for now some rest and relaxation. Tomorrow is the start of the Thirteen Days of Tango.

The “Twelve Days of Sudoku” used our regular editorial and testing team and thanks go to them for continued support. Video additions to several of these posts are expected in the future but not this month.

“Ready Layer One” and all associated content were a production by one person and all credit/blame belongs to me for the unusual experience. While a solo work, this does not mean there isn’t a long list of people to thank for ideas and love throughout the years that inspired a lot of the connections. To everyone who ever mattered in my life, and to everyone who still might, these puzzles, jokes, and other ideas are for you from deep inside my brain. The stories you share back are the return gift to sender that I’ll await through the years when the layers finally get cracked open.

Some posts still need minor edits or addition of offline content once people verify passwords, but nothing new should appear for starting explorers for awhile. For future visitors, the best trailheads are still the two links above. Other items add into the series, such as the Motivational Posters as puzzlehunt style challenges for “Twelve Days” followers, and the story/flavor text posts add to the experience but are not starting points. All posts tagged “Puzzle” have something I expect a person could discover and might want to “submit” if they figure out what and how.

Besides puzzles and favorite books and music and science history and other things, this very personal series does include aspects of mental illness/wellness, including the stigma associated with it and not being able to convince people you are ok after they’ve seen you can sometimes be ill. These are all things I have been coming to terms with in being bipolar over the last few years after several hospitalizations and large changes in professional work life. In the altered words of Brave New World, I’m claiming the right to be manic and depressed, just not most of the time. I do not want medication that would prevent me from having the kind of brain I have. My bursts of creativity do change with my mood, even when just slightly heightened, as does my willingness to be introspective and grow by sharing thoughts. A healthy Thomas balances mood but has some ups and downs within identified bounds. That said, my rate of typing and pace of thoughts even on normal days can seem overwhelming to people observing the process. This was the first series where, despite the required content being made before anything went live, the extra touches added in the downswing phase of a short creative period revealed the artist at work and frightened several people (at least based on my ability to read into comments, discord posts, etc.). It almost certainly kept many people from going down the rabbitholes for fear they would lead to nowhere, when they always were intended to lead to 3 “first round” puzzles/stories that followed the beginnings seen here.

Be sure that if I am somewhere near “we” on the mental __llness chart below, as I am today as the series “ends” its launch phase, it is mainly because of our shared memories of community together, fun memories that cross boundaries of space and time. I do think societal impacts from COVID-19 and having to lay off some team members in my science job led directly to my first severe bipolar episode, as my community of we became a party of one. WE -> I = illness. I’ve been trying to build back friendships where geography is far apart ever since, and this series is a gift to those friends that made me feel happy before and will again. Even having someone just recognize a photo as my Hovse’s cannon and sharing a memory of recovering it from Mudd made my day, so even weak (but close) connections should reach out if they find something for them.

Soundtrack: 4th album by 💀🚕🇶🇶🇶🇶☕, and other purposefully random playlists that spin out from there.

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Clued Descending a Staircase

Author/Opus: This is the 548th puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: Standard Sudoku rules.

Time Standards (highlight to view): Grandmaster = 6:15, Master = 9:15, Expert = 18:30

Solution: PDF and solving animation.

Note: Follow this link for other classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku on Google Docs.

Note 4: Thanks to Tyler Hinman for suggesting this playful title long ago for another puzzle (unused then but adopted here).

PDF

or solve online (using our beta test of Penpa-Edit tools)

Theme: Two Cool

Author/Opus: This is the 547th (A), 547th (B) puzzle from Thomas Snyder, aka Dr. Sudoku.

Rules: One of these grids obeys standard Sudoku rules with a unique solution. Solve the Sudoku. The other grid is a Just One Cell Sudoku. This grid has many, many solutions, with only one empty cell that is fixed to one value in all solutions. Find that cell’s location and value.

Time Standards (highlight to view): Grandmaster = 6:15, Master = 13:30, Expert = 27:00

Solution: PDF and solving animation.

Note: Follow this link for other classic Sudoku. If you are new to this puzzle type, here are our easiest Sudoku to get started on. More Sudoku including variations can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including classic Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our The Twelve Days of Sudoku Discussion post on the GMPuzzles Discord.

Note 3: Please check lesson notes from Dr. Sudoku on Google Docs.