Here’s this week’s Mochikoro puzzle. A little late.

solution pdf

Puzzle creator Cihan Atkay wrote two puzzles that appeared in this year’s Google US Puzzle Championship test.  On his blog, he’s posted four puzzles that were not included and they’re pretty interesting.

• Folding Sudoku - I’m not surprised that this wasn’t included since it requires solvers to cut the grid out of the paper and fold it.  (Scissors are not on the USPC allowed list.)  Still, it’s a very original sudoku variation.  I’m not sure that I entirely get it, though.
• Numberless Kakuro - Digits are replaced with letters.
• Cardboard - Requires you to fit abbreviations of former WPC hosts into a grid.  Puzzles like this show up in Atkay’s PQRST newsletter.
• Loop Lengths - Draw a single closed loop on a grid.  The loop must enclose the letters required to spell the loops length.

Sorry for the sporadic updates. It will likely be this way all summer, so this will be the last Lost Bridges puzzle until September. I will still be making other posts and I will be posting three more Mochikoro puzzles but, as I said, blog posting will be scaled back slightly for the next two months. In any case, here’s the puzzle. It should be the most difficult Lost Bridges puzzle that I’ve posted so far.

pdf solution

The winner of the 2006 Google US Puzzle Championships is Thomas Snyder who scored 270 out of a possible 285 points.  Wei-Hwa Huang finished second with 369.  Interesting to note, Thomas and Wei-Hwa were the second and third place winners in the World Sudoku Championships.  Zack Butler, who won the US Puzzle Championship last year placed third.  These three and Roger Barkan make up the US team this year.

Recently I came across this site through Digg, having the title “Very Difficult Analytical Puzzles.” I found a little more than that at the actual site. There’s a collection of logic puzzles ranging from “Very Easy” to “Very Difficult” and there was also a collection of lateral thinking problems.

We’re all familiar with lateral thinking problems which describe a mysterious situation and require a few key details from the solver in order to explain everything. When playing with friends, you get to ask yes or no questions from the person posing the problem. Most of the lateral thinking prooblems on this site were familiar to me, but what interested me most is the categories he came up with for lateral thinking problems.

• Preconceptions - Problems that challenge your preconceptions.
• Fact - Problems that arebased on fact.
• Fanciful - Problems that require a little imagination to solve.
• Semantics - Problems that require you to pay close attention to the wording of the problem.

As I think about it, these categories may be useful for classifying riddles in general.

Here’s this week’s lost bridges puzzle.

pdf solution

Here’s today’s Mochikoro puzzle:

pdf solution

Wei Hwa’s challenge this week is minesweeper and I’m fairly certain that no one will be looking for solutions. To make it interesting, he’s included some variations.

• Zero - Instead of leaving a block empty if there are no mines around it, he puts a zero in the block. This is actually slightly annoying since it doesn’t really add a dimension to the game and only requires you to click with the center button a lot more. This seems to be a bridge variation, in the sense that a lot of the later variations require a zero.
• Spider - The mine layout changes, but not for spaces that you’ve already revealed (however, flagged blocks can change.) Mostly, playing this game involves center clicking the zeroes in the middle of the board until the mines are all arounf the edges.
• Symbol - The numbers are changed to symbols. I kind of think that to make this one really challenging though, they should disable the center click. Otherwise, it’s too easy to discover early what the symbols represent.
• Memory - Blocks are never cleared. Clicking on a block reveals what’s beneath, but it’s soon covered up again.
• Knight - Numbers indicate how many mines are a chess knight’s move away. It’s fun because center clicking actually reflects this.

So, the instructions are out giving us a tate of what the test will be like. There will be a distance puzzle on the test, and 3 sudokus by my count. It’s a good idea to familiarize yourself with the puzzle types before you start. And you might want to make sure you know what exactly rotational symmetry is, or the formula for calculating a balance around a fulcrum point.

Erich Friedman’s site is always good to check out. In addition to examples of distance and weight puzzles, you will also find battleship puzzles and full hex puzzles. One of each will be on the test.

If you did last years test in preparation, you should be in good shape generally. This year’s test looks similar. The arrow ring puzzle recently mentioned on Zotmeister will be in this year’s test as well.

The most interesting twist is a kakuro variation that also includes negative numbers. Happy puzzling all.

And the sodoku silliness continues. Here’s the link where you can buy sudoku toilet paper (found through Idiot World). I think they made a real design error here. Clearly there should be one puzzle per sheet, but one of the puzzles is clearly cut off at the perforation. I wonder if anyone has bought it just to solve the puzzles.

Coming in just at the buzzer East Coast time… the tenth and final (for now) Wordstream puzzle. This puzzle is not only too big to fit in this space, it’s too big to fit on the same page with its word list. The wordstream for this puzzle is made up of all 50 states and is laid out in a 30X30 grid. This has been the trickiest puzzle yet when it came to making sure there was a single unique solution. You’ll notice that NorthCarolina and SouthCarolina would very often fit in the same spots. (There are a few others too.) Enjoy!

pdf solution

I came across this post about a puzzle called han’en that claims to combine elements of sudoku and kakuro.  Currently, the blog that this post comes from is dedicated entirely to the puzzle.

The puzzle is made up of a six by six with some numbers filled in.  At the end of each row and column is the sum for that row or column.  Each digit may only appear four times so that all of the numbers in the grid add up to 180 and this is where the puzzle get’s it’s name.  Han’en is Japanese for semicircle, and a semicircular arc has 180 degrees.  All of the normal kakuro rules apply.  No digit can be used twice in the same sum.  Only the digits 1-9 can be used. Essentially, it’s a 6X6 square kakuro with the added rule that each digit must be used only four times.  There’s also a variation called perfect han’en in which each row and column sums to 30.

Puzzle Bowling is a little flash puzzle game that I found through gamertech.com. The game involves shifting the grooves in a bowling alley so that the ball hits the pins. You have to knock down all of the pins and then knock down a trophy to make it to the next level.

This week’s Lost Bridges puzzle is slightly larger than previous weeks. Enjoy!

pdf solution

Here’s another puzzle variation that involves chess: Chess Battleships. The most recent ForSmarts issue features one such puzzle.

The puzzle is a basic battleships puzzle with the extra challenge that 5 chess pieces must go on 5 gray squares. The chess pieces and ships must be arranged such that each chess piece attacks each type of ship exactly once.