PN Trivia Scavenger Hunt: Answers & Winner!

[Image courtesy of Alaris Health.]

Thank you to everyone who entered our anniversary trivia scavenger hunt! Plenty of solvers, puzzlers, and PuzzleNationers tried their hand at answering all five questions before the deadline at midnight on Wednesday, and many succeeded!

Alas, there can be only one winner. But before we get to that, let’s look at the answers, shall we?

PuzzleNation Anniversary Trivia Scavenger Hunt

1.) One of my favorite recurring features is Puzzles in Pop Culture, where I explore puzzly moments in television, film, and literature. We’ve discussed Sherlock, Hell’s Kitchen, and even Gilmore Girls in installments of Puzzles in Pop Culture.

Question: How do you solve the four gallons of water puzzle?

Answer: There were actually two answers featured in the August 19, 2014 post “Puzzles in Pop Culture: Die Hard with a Vengeance” referenced in this question. Here’s the answer our winner submitted:

1. Fill the 3-gallon jug and pour the water into the 5-gallon jug.
2. Refill the 3-gallon jug and pour the water into the 5-gallon jug until the 5-gallon jug is full, leaving 1 gallon in the 3-gallon jug.
3. Empty the 5-gallon jug and pour the 1 gallon of water from the 3-gallon jug into the 5-gallon jug.
4. Fill the 3-gallon jug again and empty it into the 5-gallon jug, leaving exactly 4 gallons in the 5-gallon jug.

2.) You can’t talk about puzzles without also discussing games, because there’s so much overlap between the two. Game reviews from a puzzle solver’s perspective have become a part of the fabric of PuzzleNation Blog, as has creating your own puzzles and games from scratch.

Question: What’s the name of the DIY game that only requires a bunch of identical blank pieces of paper (like index cards) and something to write with?

Answer: Discussed in our September 15, 2015 post “DIY Pencil and Paper Puzzles,” this game is known as 1000 Blank White Cards.

3.) Naturally, if you’re going to talk puzzles, Sudoku is going to be part of the conversation sooner rather than later. We’ve not only explored the history of Sudoku here, but we’ve been a part of it, debuting brand-new Sudoku variants created by topnotch constructors.

Question: What do you call two overlapping Samurai Sudoku?

Answer: We posted many different Sudoku variants in our December 4, 2014 post “The Wide World of Sudoku,” but the puzzle in question is known as Shogun Sudoku.

4.) A fair amount of puzzle history, both past and present, has been covered here over the last five years. We’ve examined cryptography in the American Revolution, the Civil War, both World Wars, and beyond. We’ve celebrated the one-hundredth anniversary of the crossword. And we’ve even discussed scandals in the puzzle world.

Question: What are the names of the programmer and crossword constructor who first uncovered the curious pattern of puzzle repetition in USA Today and Universal Uclick puzzles that eventually led to the ouster of Timothy Parker?

Answer: As discussed in a series of posts entitled “Puzzle Plagiarism,” the programmer’s name is Saul Pwanson and the constructor’s name is Ben Tausig.

5.) In the Internet age, memes and fads appear and disappear faster than ever. A picture or a joke or a news story can sweep the world in a matter of hours, and then vanish forever. On a few occasions, the Internet has become obsessed with certain optical illusions, and we’ve done our best to analyze them from a puzzler’s perspective.

Question: The creators of The Dress appeared on what talk show to put the mystery to bed once and for all?

Answer: Discussed on March 6, 2015 in a Follow-Up Friday post, the mystery of The Dress was laid to rest on The Ellen DeGeneres Show.

[Image courtesy of ClipArt Panda.]

And now, without any further ado, we’d like to congratulate our winner, who shall remain nameless. After all, like a lottery winner, she doesn’t want to be mobbed by those hoping for a piece of the action. =)

She’ll be receiving her choice of either a Penny Dell Crosswords App puzzle set download OR a copy of one of the puzzle games we’ve reviewed this year!

Thank again to everyone for playing and for celebrating five years of PuzzleNation Blog with us. We truly could not have done it without you!

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PuzzleNation Product Review: Color Cube Sudoku

[Note: I received a free copy of this product in exchange for a fair, unbiased review. Due diligence, full disclosure, and all that.]

Sudoku is one of the most popular pen-and-paper puzzles in the world. It’s found in numerous daily newspapers, puzzle books, and smartphone apps.

After years of tackling regular Sudoku, Extreme Sudoku, Word Sudoku, Mega Sudoku, Samurai Sudoku, Geometric Sudoku, Sum-Doku, and numerous other variations, you’d think the puzzle community at large would’ve exhausted every possible version of Sudoku.

Enter the crafty folks at ThinkFun, who have put a unique spin on another Sudoku variant: Color Sudoku. In Color Sudoku, you have nine colors to arrange instead of numbers.

ThinkFun has upped the ante with Color Cube Sudoku, their latest puzzle-game, by combining the twisty-turny cube possibilities of a Rubik’s Cube with Sudoku-style deductive solving.

It seems like a simple enough set-up. You’ve got a tray and nine multi-colored cubes. Each cube has four of the six possible colors: green, red, blue, yellow, orange, and white. And it’s up to you to arrange the nine cubes in the grid in a 3×3 pattern so that each color only appears once in each row and column.

But that arrangement already introduces complications. Unlike a pen-and-paper puzzle, where you can place any number (or in this case, any color) in any square you choose, the preset color arrangements on each cube limit your choices.

If you need a blue square in the first row, sixth column, given the cubes available to you, you might end up with a second yellow square in your row. Which means, instead of needing a new cube, you need to change one of the cubes you’ve already placed and try again.

What once seemed simple now offers a greater challenge.

But, like many ThinkFun puzzle-games, the more you play around with the possibilities, the more you begin developing new strategies and get into the psychology of the puzzle itself.

Once you’ve placed a few of the cubes, next-level deductive reasoning kicks in, and you can eliminate certain possibilities and begin working more than one step ahead at a time.

For instance, if you’ve placed two cubes in a column, you’ll know you need to change one of the cubes if the third cube will need a green spot in both columns. Since that’s impossible, even without placing the third cube, you know you need to change one of the two you’ve already placed. Which means you’re preventing wasted moves and pushing closer to an actual solution.

Whether you’re tackling Color Cube Sudoku alone or with partners, whether you’re trying to crack a regular 6×6 pattern or taking a whack at some of the variant challenges they suggest — like knight’s paths and other difficult patterns — this is a deduction puzzle that feels like play instead of work.

When I tested this out with a fellow puzzler, we immediately began playing it in a slightly more competitive way. One of us would place a cube, and then the other would place a cube, and we would keep going until no cube could be placed.

You can end the game there, or you can take it a step further, and introduce rules where moving or shifting previously-placed cubes becomes part of the game in order to extend the puzzly gameplay. Heck, if you go long enough, it eventually becomes a race to see who can actually solve the Color Cube Sudoku layout first!

The designers state that there are 2,641,807,540,224 different ways to arrange the 9 cubes, and with seemingly endless variation in such a simple set-up, this is one puzzle-game you can put down and return to numerous times without burning out or feeling like you’ve conquered it forever.

Color Cube Sudoku is available for $19.99 from ThinkFun and select retailers!

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Sudoku Around the World!


Sudoku is the most popular pen-and-paper puzzle since the crossword. No other puzzles come close. Whether it’s in your local paper, our iPad app, or one of the magazines offered by our friends at Penny/Dell Puzzles, chances are you’ve solved a Sudoku puzzle at one time or another.

And the solving experience is an integral part of its success. When you look at a Sudoku grid, you instinctively know what sort of puzzle you’re dealing with and what the goal is. You don’t need the instructions or any elaborate explanations. You can simply dive right in.

That sort of simplicity and accessibility gives Sudoku major appeal, and has contributed to its success as an iconic puzzle worldwide.


Look at this stack of puzzle books from around the world, loaned to me by a friend of the blog!

There are Sudoku books in Russian, French, Japanese, and other languages! And yet, you could pick up any one of these magazines and start solving immediately.


Here are two Samurai Sudoku from a Russian puzzle magazine. Again, these are identical to the overlapping grids you find in the States.


I did, however, encounter a few intriguing variations I was unfamiliar with as I perused these magazines published by 777.


Instead of providing sums in smaller boxes within the grid like Sum-Doku puzzles, or along the edges like Kakuro, these puzzles offer totals that correspond to the three diagonal boxes in a line a given arrow points to.


In this Sudoku variant, there are no repeats of the numbers 1 through 8 in a given row or column, but there are also no repeats within each group of connected circles.

Again, although I couldn’t read the instructions for these new puzzles, I was easily able to figure out the mechanics of each and start solving within a few minutes. Very few puzzles have that sort of universal accessibility.


While I’m very familiar with Kakuro (or Cross Sums) puzzles, I’ve never encountered cut-style grids like these. I just love the simple elegance of these diamond-shaped grids. Very eye-catching.

Believe it or not, this is just a sampling of the hundreds and hundreds of Sudoku magazines and puzzle books released over the last decade.

Although the puzzle as we know it has been around since the ’70s under other names (To the Nines and Number Place, among them), it was only relatively recently that it exploded in popularity, becoming a true cultural touchstone and undeniable puzzle phenomenon.

[For another blog post exploring puzzle books from around the world, click here!]

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The Wide World of Sudoku


[A classic Sudoku grid with a colorful twist, where the 3×3 blue squares also have all 9 numbers inside them. One of many MANY Sudoku variants. Grid from]

For more than a century now, crosswords have been the premier pencil-and-paper (or pen-and-paper, if you’re confident) puzzle, but a close second would have to be Sudoku, which has exploded in popularity over the last decade or so.

The simple concept behind Sudoku — a 9×9 grid arranged so that the numbers 1 through 9 only appear once in each row, column, and 3×3 square — is easily modified for any difficulty level, from beginners to topnotch solvers.

The classic form of Sudoku, originally known as Number Place or To the Nines, is instantly recognizable.


[A Sudoku grid from PuzzleNation’s own free Classic Sudoku app for iPad.]

But virtually any set of nine different symbols, characters, numbers, or letters can be used as clues for a Sudoku-style solve. That gives us variations like Picture Sudoku or Color Sudoku, where the same deduction is involved, but the solution is a bit more vibrant.


[A color Sudoku from]

Word Sudoku follows the same concept, replacing the numbers 1 through 9 with letters, allowing for the added bonus of a 9-letter word reading out along one of the rows. I’ve seen Word Sudoku variations in all sorts of languages, which is neat, because you can still solve the puzzle even if you don’t know the language; you’re simply choosing different symbols.


[A Word Sudoku from Magic Word Square on Blogspot.]

Using letters instead of numbers often factors into larger Sudoku puzzles. While Penny/Dell’s Mega Sudoku is a 16×16 grid using the numbers 1 through 16, other large-scale Sudoku puzzles use letters instead of numbers above 10, while others go so far as to remove the numbers altogether, giving you the option of puzzles that span nearly the entire alphabet!


[A 25×25 monster Sudoku grid using letters, courtesy of]

And since we’re already discussing bigger Sudoku puzzles, it’s worth mentioning smaller Sudoku puzzles. Often called Mini-Sudoku or Sub-Doku, these puzzles start at 4×4 grids (using only the numbers 1 through 4) and increase in size all the way up to the standard 9×9 grid.

Those are just the puzzles that use standard Sudoku rules. There are numerous types of Sudoku that add new rules or curious wrinkles to the standard solve.

Perhaps the most famous variant is known as Extreme Sudoku, Diagonal Sudoku, or X-Sudoku, and there’s one crucial difference: the numbers 1 through 9 also appear only once along each diagonal. This additional rule helps with solving, but Extreme Sudoku puzzles often have fewer set numbers in order to keep the difficulty level interesting.


Another popular variation is known as Jigsaw Sudoku or Geometric Sudoku. These puzzles abandon the standard 3×3 boxes, instead using various Tetris-like shapes within the 9×9 grid. Each of these pieces contains each number 1 through 9, and the standard rule of no repeats within a row or a column remains.

These puzzles can either have random shapes or shapes with the same diagonal symmetry that rules both crossword grids and the placement of set numbers in classic Sudoku grids.


[A Jigsaw Sudoku grid from]

Some variations involve more deduction as well, like Neighbor Order Sudoku or Greater Than Sudoku. These puzzles feature small arrows that indicate whether the number in a given square is larger or smaller than its neighbor.

That’s just the start of math-based Sudoku variants that exist. Sum-Doku or Killer Sudoku uses the standard one-per-row, column, and 3×3 box Sudoku rule, but also adds numerous smaller Tetris shapes and boxes, each with a total. The numbers within that smaller box add up to that total.

Those totals are a crucial aid for solving, since Sum-doku puzzles often feature many fewer starting numbers. (The shapes of the smaller boxes often follow the diagonal symmetry of the set numbers.)


[A Sum-Doku grid from]

Another popular variant involves overlapping Sudoku grids. You could have two 9×9 grids that share one 3×3 box, or two 9×9 grids sharing four 3×3 boxes, or you could have more grids overlapping in all sorts of ways.


[A quadruple overlapping Sudoku grid, courtesy of the forums of]

The best known overlapping Sudoku puzzle is probably Samurai Sudoku, which features five 9×9 grids, one at the center and one at each corner, so the 4 corner 3×3 boxes of the center grid link the puzzle together.

Check out this masterpiece I discovered on


Not only is it a Samurai Sudoku with diagonal symmetry for all the set numbers, but each of the four corner grids operates under a different set of variant rules.

The upper left grid uses Extreme Sudoku (or Diagonal Sudoku) rules, the upper right grid is an asymmetric Jigsaw Sudoku (or Geometric Sudoku), the lower left grid has shaded the location of every even-numbered number to aid your solving, and the bottom right has two shaded ribbons weaving throughout the grid, each of which also includes each number from 1 through 9 once.

As you might expect, there are plenty of variations of Samurai Sudoku. My personal favorite is known as Shogun Sudoku; it’s two linked Samurai Sudoku grids — meaning there are ELEVEN linked 9×9 grids — and there are even larger variations out there for the solver who simply can’t get enough of overlapping Sudoku puzzles.


[Upper left: Tight Fit Sudoku, Upper Right: Thermo Sudoku,
Lower Left: Arrow Sudoku, Lower Right: Consecutive Sudoku.]

Our friends at Penny/Dell Puzzles have several titles that offer a variety of different Sudoku puzzles. The four grids above all appear in various issues of Will Shortz’s WordPlay, all courtesy of Sudoku constructor Thomas Snyder.

You should also check out the Sudoku Spectacular title (featured in our Holiday Puzzly Gift Guide!) as well as their upcoming Will Shortz’s Sudoku title.

I would also be remiss if I didn’t mention the mathier cousins of Sudoku.


Kakuro, also known as Cross Sums, follows the same no-repeats rule of classic Sudoku, but the grids are much closer to Crosswords. The numbers along the top and left-side are the total for each row or column, and they are the primary clues for solving the puzzle. Kakuro rarely features set numbers the way Sudoku does, instead opting for a single filled-in row or column to get the solver started.


[A 6×6 KenKen grid, courtesy of The Math Magazine on Blogspot]

KenKen takes the addition from Sum-Doku and adds subtraction, multiplication, and division to the mix. Each box has a number and a mathematical symbol. The number is the total, and the symbol is how the missing numbers interact to reach that total. For instance, in the upper right corner of the grid, there’s 24X. That means the two missing numbers from that box, when multiplied, equal 24.

And since this is a 6×6 grid, following the same one-per-row and column rules of Sudoku, you know that 4 and 6 are the missing numbers in that box, but you don’t necessarily know where to place them yet.

When it comes to Sudoku, the variations on shapes and layouts are seemingly endless. I’ve seen diamonds and snowflakes, cubes and five-pointed stars, in all sorts of sizes. You can get Samurai Sudoku with 6×6 grids, Jigsaw Sudoku in miniature, and Word Sudoku with Egyptian hieroglyphics.

While researching this post, I encountered this marvelous Sudoku variant, which the constructor calls Star Sudoku.


The numbers 1 through 9 appear once in each triangle, and there are no repeats along any row or slanted column. This puzzle is not only clever, it’s flat-out neat.

So, fellow puzzlers, what’s your favorite variation of Sudoku? Or do you prefer to stick with the classic version? Let me know! I’d love to hear from you!

Thanks for visiting PuzzleNation Blog today! You can share your pictures with us on Instagram, friend us on Facebook, check us out on TwitterPinterest, and Tumblr, and be sure to check out the growing library of PuzzleNation apps and games!