Puzzles

Online Puzzles

February 27, 2006
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There always seems to be more and more of these popping up, so I guess they deserve a mention.

Online puzzles are web-based puzzle games where solving puzzles leads you through a series of web pages. For each page in an online puzzle, the goal is “to get to the next page” but how exactly you manage to do that varies from page to page. Often you will have to click somewhere on the page and then enter a password, but you’re just as likely to have to enter a new URL suggested by the puzzle on the page. Often, you will have to look at the page source or find a hidden file. The challenge of the puzzles, more than anything else, is figuring out what exactly you have to do.

I think the most famous example of this game is notpron, which I played for a few screens. Then I reached a screen that seemed to want me to use a program that comes with Windows, and well… I’m not a Windows user and that was that.

There are dozens of this kind of game on the internet now. Most of them are trying to get a piece of the success of notpron. You can find a good list on the wikipedia page.

Moving Image Jigsaw

February 27, 2006
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Through the Funny Emails blog, I found a flash jigsaw puzzle where the image changes while you’re trying to assemble it.  This is a great idea even if this isn’t the best implementation.  The puzzle is extremely simple and the image is mostly blue sky.

I hope that someone is working on a better version.

World’s Largest Puzzles

February 24, 2006
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I encountered two “world’s largest” puzzle stories today. One was about a crossword, the other was about a jigsaw puzzle.

Through Crossword Puzzle Links, I found a place where you can buy the “World’s Largest Crossword Puzzle” according to the Guiness Book of World Records. According to the site:

Breaking the 1996 Guinness record, this crossword hangs on a full seven feet by seven feet of wall space and has 28,000 clues for over 91,000 squares.

The second story was a BBC story about a man who completed what “could be the world’s largest commercially available jigsaw.” The puzzle was 10 and a half feet long and 5 feet wide.

Forsmarts Puzzles

February 23, 2006
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Forsmarts has published Issue 20 (or issue 10 of season 7; I’m not really sure how that works, but I haven’t been visiting the site for very long) and this issue contains three interesting puzzles. Forsmarts, is a semi-annual puzzle competition that includes puzzles on the more difficult end of the spectrum.
Fair warning: What I write below might be a little confusing if you have not actually seen the puzzles.

The first puzzle is based in a hex grid and requires you to place some number of 3-cell figures into the grid. Each cell in each figure will contain a number that corresponds to the number of other filled cells in a direct line with it. Some partial figures are already placed. This puzzle is a standard logic problem with very specific constraints. It essentially says, here are some digits. For each digit, place the corresponding number of additional digits in hexes that are within a direct line. And they must be adjacent in groups of no more or no less than three. Of course, it’s the last constraint that’s the kicker.

The second puzzle is a dominoku. It’s a 7X7 grid jigsaw sudoku (of course, all 7X7 sudokus must be jigsaws) but instead of the placing digits one at a time, you have to place from a given set of dominos. Essentially, you have to place the digits two at a time. It’s an interesting sudoku variation and one that requires very few digits given at the start.

The third is an optimization puzzle, to be solved by the best possible solution. It requires you to write numbers frome one to ninety nine (in english and in any order) into a grid, starting from the top left and filling in left to right from the top line to the bottom. The catch is that a given letter can be repeated only once in any row or column. The goal is to include as many digits as possible. So, quickly, the largest possible grid is 16X16 since the numbers share 16 letters in common. However, it may not be possible even to come up with one row with 16 different letters, let alone 16. I think the best solution will involve finding a row length that will allow you to have a maximum number of rows. But that’s only a guess, I haven’t come up with a solution yet.

One Billion Mazes

February 20, 2006
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Through a homeschooling blog, I came across a website boasting one billion mazes.  I certainly don’t have time to verify this, but this seems to be true.  (Ok puzzle maniacs: If you did one maze a minute, how long would it take you to finish one billion puzzles? Answer at the bottom.)

These mazes must be computer generated (the alternatives are too hard to imagine, really.)  They are all in printable PDF form where page one is the maze and page two is the solution.  And they vary considerably in difficulty.  If you’re into mazes, check it out.  But I suggest you don’t try to solve them all.

On the same blog post that led me to the mazes, there was also a brief description of a “touch Rubik’s Cube.”  It’s a standard Rubik’s Cube that has six different materials covering the six different sides so that you can solve the puzzle without even looking at it.

(Answer to above question:  Assuming you took no breaks and lived long enough, you would finish the mazes in just over 1902 years.  Or just under two millenia, depending on how you look at it.)

Kakuro – Cross Sum

February 19, 2006
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kakuroI was at a book store Friday night and noticed a few kakuro books nestled into a display of sudoku related books. It looks like publishers are thinking that the current popularity of sudoku can help them sell book about another puzzle with a Japanese name.

Of course, kakuro (or cross-sum) puzzles aren’t new, but the buzz about them in the US has only risen very recently. Major web sites related to kakuro have shown up in the past six months, and it’s not hard to find blogs that discuss the puzzles and how to solve them.

I’ve often heard sudoku called a number crossword, which seemd odd too me since a sudoku is nothing like a crossword. There are, however, many similarites between crosswords and kakuro. A kakuro grid more closely resembles an American crossword grid. In a crossword, you are given a clue and the answer is limitted by how many blocks are available and by intersecting answers. Likewise with kakuro, you must find digits that sum to a specific value but you are limitted by the number of spaces and the intersecting sums. Additionally, no sum can contain the same digit twice.

It’ll be interesting to see if kakuro can become as big as sudoku and, if it does, what other kinds of puzzles will become popular after it.

Image from wikipedia.

Valentine’s Sudoku

February 14, 2006
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I came across the Valentine’s Day themed sudokus through Ian’s Messy Desk.  When I first saw the title of the post, I wondered what exactly a Valentine’s Day sudoku was.  Apparently, its a regular old sudoku with the squares colored and numbers filled in to make a love-themed picture.  It might have been nicer if the colors somehow figured into the solving of the sudoku, but still they’re fun sudokus for the day.  You could print them up and put them on Valentine’s cards for puzzle-lovers.

Petals around the rose

February 13, 2006
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I was introduced today to a puzzle called “Petals Around the Rose” on the nan (not a nerd) blog. This is the kind of puzzle that might be called a “definition puzzle.” The solution to the puzzle is trivially easy, the trick lies in defining the problem.

The puzzle set up goes as follows. Roll five six-sided dice. Then answer: How many petals around the rose? There is only one answer. The answer is always even and, sometimes, it’s zero. To try it out, there’s a flash based simulation on this page. I’ll give the author of the page the benefit of the doubt and assume it works in some browsers, even though it didn’t work in mine. Another implementation of the puzzle can be found here.

They say that some solve the puzzle quickly and others require a long time. Having solved the puzzle, I can say that it’s not the most diabolical of its kind.

Sudoku variant: Mystery Godoku

February 13, 2006
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On the blog for Hidden Staircase Mystery Books, I came across yet another sudoku variant. HSMB’s “godoku” uses letters instead of numbers (a standard variant that I mentioned yesterday) and the letters can be rearranged to form the answer to a clue (in this case a mystery novel) that will fill one row or column.

The clues on this site are all mystery themed, but the theme can be whatever you want. And you don’t need to get the clue to solve the sudoku. They have a new puzzle up now, as well as archives of past puzzles.