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The hardest puzzle I wrote for the USPC was originally intended to be presented as a subtle “surprise”. The rules would have covered what thermometer shapes do (strictly increase from bulb to flat end), but would not have been explicit that those shapes could reach outside the grid. So finding a grid with no external numbers but with many external shapes would have been a manageable but perhaps unexpected surprise. But it was decided to just be explicit here, and with some other authors in the last few months having used the same external clue ideas with skyscrapers (including myself here with an Even/Odd Skyscrapers after I knew the fate of this puzzle) it’s not clear if this would have been unexpected anyway.

I thought this was an interesting extension of some inequality skyscraper concepts I’ve seen elsewhere. My first attempt at this puzzle type was judged very elegant and far too hard. My second attempt kept one of these two traits and made it onto the test. Like the TomTom, this variation seemed to get pretty good reviews, but I do know some solvers who fell into the trap of thinking an outside number blocked that number from appearing inside the grid.

PDF

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

Theme: No given numbers, and full clue cell symmetry

Rules: Standard Skyscrapers rules. Also, as in Thermo-Sudoku, digits must be strictly increasing in all thermometer shapes from round bulb to flat end.

Answer String: For the USPC, the answer string was the internal cells in the 4th row and 7th row. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

While I still want to find a good name for this variation of TomTom (Tight Fit TomTom matches the genesis story well but is probably not the best name for longevity), it was a style idea that strongly encouraged me to write for the USPC this year as it seemed a great place to debut it.

The idea actually came from Craig Kasper during a discussion of puzzle styles and possible variations. Craig didn’t think he could do it justice, but he offered it to me and I knew instantly it was a great concept to save for the future — with the USPC as the obvious first destination if it could work. I wrote two Tom/Tom puzzles (also probably not the best name — maybe in the comments people can recommend others?). The first was an easy one (10 pointer?) that became the example. The second was a tougher puzzle that has been called undervalued for 20 points by most people commenting on it. Perhaps the break-ins were not as easy to find?

The biggest struggle with the style was how to format it well; you’ll find that both of these puzzles use slashes in cells that would not normally contain the clue digit to leave more space in the fractional cells for writing numbers. Palmer’s pre-USPC example uses shaded cells and this might be a more productive route going forward. I have plans to make a bunch of TomTom variety books/puzzle packs focused on different math concepts and will probably make one around this variation when I get some larger tasks off my plate. Removing some of the extra trickiness of these samples and having simpler fractional values and even fractional clue targets should make this a good extension of TomTom puzzles for education purposes. I can even turn single cell cages into non-trivial entries!

I hope you enjoyed this variation as much as I enjoyed making it work.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between “big” sudoku and “small” number entry modes.)

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between “big” sudoku and “small” number entry modes.)

Theme: Cage geometries, and the logic of the solve and new fraction rules primarily

Rules: Variation of standard TomTom rules. The indicated ranges are larger than N x N (1-6 and 1-8 respectively), and some cells containing slashes require two digits to be placed. These cells should be treated as fractional values (top value over bottom value) for the purposes of solving the puzzle.

Answer String: For the USPC, the answer string was the 5th row and 5th column of the larger puzzle. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution 1: PDF
Solution 2: PDF

I received a lot of “pre-criticism” about having made a Counting Puzzle for the USPC. I have been rather outstated as a solver in not liking these puzzles because of the difficulty of confirming one’s answer — particularly in the old -5 point days for a mistake that would frequently cost me for even attempting and getting close to the right answer. And I often don’t get the choice to skip it when I’m close to finishing the test.

But that doesn’t mean I’ve never been called on to write Counting Puzzles. I wrote a GAMES article/Puzzlecraft chapter on the topic. And I gave it another attempt on this USPC. Call it an experiment to see if I could make anything my audience would accept as a good puzzle.

My first concept was to make a heavy path puzzle with lots of forced segments due to arrows, but not a single solution to give it a “counting” aspect. While I figured good solvers would be able to get to a “trivial” state to count a handful of total paths, all of my initial designs ended up feeling more like a broken path puzzle than a good counting puzzle so a changed goals slightly. I wondered: can I make a few very simple counting challenges work together with some simple math to be a fair challenge. Basically, something where good observation could reduce the problem into something much more tractable. And if this is testing both observation and problem solving skills in an unfamiliar setting, all the better.

Even with the “simple” format below that even had the surprise of very basic multiplication built in, the successful answer rate was quite low compared to my own expectations. And at least one solver has complained about getting 99.991% of the correct answer and getting zero credit. In my evaluation, with three small counting puzzles and a meta puzzle of building the math equation, that answer is 75% correct in the same way some of the answers in the 52k range were. All from counting one of the component puzzles one lower than expected.

So, did you think this was an appropriate USPC challenge? Did this soften or strengthen opinions against counting puzzles? Are counting puzzles still the brussel sprouts of the USPC buffet? I’ve only heard positives from people that actually got the puzzle correct so I do have to think score results often bias counting puzzle reviews (my strongly negative reviews have certainly followed my average score of -5 on these puzzles over the years).

PDF

Theme: Symmetry, mainly

Rules: Count the number of different paths from Start (S) to Finish (F). You cannot use an intersection or a path segment more than once. Path segments with arrows can only be used in the indicated direction.

Answer String: For the USPC, the answer string was the number of paths. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

And if you want an extra challenge, solve this bonus puzzle where an arrow has been removed. It’s one step up from the original puzzle but should be just as simple to break into constituent parts if you’ve mastered the first.

Last Saturday finished another 6 week cycle of offerings from Grandmaster Puzzles. It also finished a rather busy 6 weeks of puzzle construction and testing, including three different puzzle championship rounds. Two of these have now been hosted (the US Sudoku Qualifying Test/Grand Prix Contest, and the US Puzzle Championship) and one will be a future surprise. This gives me reason to think a pause for some reflection and discussion about some of these puzzles would be a valuable use of the “gap” time before our next spurt of new puzzles and possibly new genres begins. [It also gives me a chance to hopefully address some server issues.]

The USPC is one of the few championships that follows the World Puzzle Federation’s model of puzzle balance including observational puzzles, word manipulation puzzles, and often some “trick” puzzles alongside a mix of classic constraint satisfaction types and variants. I figured — given existing contributors — that I would be most called upon to make some innovative word and observational puzzles alongside some original (read: previously unseen) variants that would hold new surprises for all solvers. The first puzzle I wanted to highlight is one that is meant to be recognizable and friendly to even the casual solver: the USPC Word Search.

I had a few ideas in mind this year for creating an interesting word search, and settled on a variety rebus gimmick where entries may or may not contain a shortened set of characters in a single square. Having previously used digit word phrases for a Sudoku Masterpieces puzzle (Some Err1ous Spelling!) and having much of that research on hand, I took my time getting a good interlinked set of “Digi2rds” together for the USPC puzzle. The missing middle shaped like an octothorpe was another goal I had in mind to give the puzzle some character. I also laid some traps around the middle for solvers trying to intuit words too soon. While many solvers will turn their noses up at a word search, I still see great value in having such puzzle styles represented on a puzzle championship. I hope I managed to give an intriguing challenge with the puzzle below.

PDF

or solve online (using our beta test of Penpa-Edit tools; use tab mode to shift between line drawing, letter/number entry, and shading modes)

Theme: Hidden Numbers

Rules: Standard Word Search rules. Also, a digit may be used in place of its letters when spelled out. For example, “DIGIT WORD SEARCH” might appear in the grid as “DIGI2RDSEARCH”. 25 characters are missing from the grid and must be identified to complete the puzzle.

Answer String: For the USPC, the answer string was the 25 missing characters in order. For this week, you can just hit the solved button on an honor system if you think you’ve solved it.

Solution: PDF

On May 26th, in recognition of our Contributing Puzzlemaster Grant Fikes’ birthday, a Sunday Surprise contest was posted. 29 solvers have completed the puzzle and all were added to a drawing Grant describes here.

The winner of the random drawing is FoxFireX, who will receive a copy of Battle of LITS.

Today’s surprise marks the occasion of Grant Fikes’ 26th birthday. Grant has written a surprise puzzle hunt-style puzzle that will solve to a two word answer. This is likely more challenging than our earlier “Word Search” surprise on April 1st, but we hope it is enjoyable to those who give it a shot while celebrating Grant’s birthday.

Note: the first 26 solvers (or all those who solve it within a week if fewer than 26 solve it by then) will be entered into a random drawing for a copy of Grant’s “Battle of LITS” board game.

PDF

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

Answer String: Enter the two word answer in all capital letters, with a single space between words.

Solution: PDF

Update (6/2/13): There have been 27 solvers in the week since this puzzle posted and all of those names will be placed into a drawing sometime shortly. Watch here for further updates.

**While this was initially not a numbered Grant opus, we are calling it #48 for our site count.

I knew when constructing puzzles for this past week that it would end up pretty tough across the board. I had certain themes in mind and when constructing for a particular goal you cannot always tailor the timing precisely. I believe — except for Monday’s puzzle — everything was rated for at least 5 minutes. It is probably asking too much to expect a full week to “feel perfectly balanced” when there are six different styles being presented.

So, while it may be impossible to avoid “hard” weeks in the future, this did seem an apt time to return to discussing some of these puzzles. I got a specific request to describe Saturday’s Battleships in logical terms, so that is what I’ll cover today.

(more…)

A few weeks ago Giovanni P. asked what our visitors might think about “other puzzles.” His question was specific to word puzzles, but this week I put the question to the test when I posted our first “Puzzle Hunt” puzzle. The Monday puzzle was not announced as such. Instead it was meant to just look like an April Fools joke. But it already has the most FAVEs of any puzzle on the site. So what are “Puzzle Hunt” puzzles and what was really going on with that word search?

(more…)

Last week saw the release of Puzzlecraft: The Ultimate Guide on How to Construct Every Kind of Puzzle, a really incredible project with Mike Selinker that was an extension of our GAMES Magazine articles that have run for many years (I joined Mike around article #48 when he wanted to write on how to construct Battleships. I’ve been part of the process ever since as we now approach #100). The title seems overly broad, but I challenge anyone to come up with a puzzle style that isn’t covered in the book.

Last week also saw Mike and I finish construction on a book you’ll get to see next year, Tile Crosswords, a word puzzle style that we developed out of the logic puzzle “Crack-It-On” that first appeared at the WPC in Hungary in the late 90s. You might not picture me as someone who fills grids with letters that have a meaning when considered as intact strings, let alone then provides sets of letters outside the grid that also form strings that evoke the sets of letters that are in the grid — certainly if I write about making word grids and cluing them that way it would seem impossible that I even speak English — but it is something I’ve been increasingly finding joy in doing.

The reason I mention all this is to give you some forewarning that over the coming months we may have other puzzle types than just sudoku and abstract logic puzzles here. Just as with the Hidden Contest that ended last week, I intend Grandmaster Puzzles to have all the kinds of puzzles I would like to solve, but with a friendly mix of easy to hard and lots of different genres so that if today is not your cup of tea, then tomorrow probably is. You may only think of me as a logic puzzle constructor, but working with Mike over the last few years has really developed my puzzle-making chops in almost every area.

Whatever puzzles we release here, they should still be worthy in their genres of being called masterpieces.

Sincerely,
Dr. S