For Day One, my calendar calculation routine, I recently released a custom-designed calendar clipboard which helps make the feat visible to a small crowd.

In today's post, I'll show you how to put together your own calendar prop inexpensively, and even some other directions you can take the basic idea.

To start, you'll need a magnetic dry-erase board with a blank calendar pre-printed on it. I used an 11 by 14 dry erase calendar from Expo, which comes with two magnets. The two important features in the board are that it be magnetic, as well as small enough to use and carry for a performance, while still being visible for your audience. You'll also need to make sure your chosen board has 5 weeks to mark.

You'll also need a dry erase marker (usually included with dry erase calendars), a dry erase eraser, and a permanent marker, such as a Sharpie. Optionally, you may want a ruler for making your marks consistent. If you choose a ruler, I suggest a cork-backed ruler to minimize damage to the board.

What you're going to do is use the permanent marker to write the dates in the squares from 1 through 28, similar to the way the calendar clipboard is laid out. Most dry erase calendars have a small space in a corner for the date, such as the corner notches seen on this dry erase calendar, but for better audience visibility, you'll want to use as much of each date's square to write the date.

If you prefer, you can use the ruler and a dry erase marker to create even guidelines for your dates first. Personally, I didn't do this. In performance, I need to write and/or erase 29, 30, and 31 on the board, and those will usually be written freehand, so they tend to stand out if the other dates aren't written freehand, as well.

What happens if you make a mistake when writing with a permanent marker on your dry erase calendar? Don't worry, there are numerous ways to remove permanent marker off of your dry erase board. The simplest and most surprising of them uses only a dry erase marker and eraser to remove permanent marker.

Once you've written the dates from 1, in the upper-leftmost square, through 28, in the rightmost square of the 4th week, using large numbers as discussed above, you can put the permanent marker away.

Not surprisingly, most dry erase calendars have the days of the week permanently marked at the top. Yet, you need to be able to change the days of the week in routines like Day One. To solve this problem, I simply use magnets printed with days of the week. This is why I emphasized the importance of a magnetic dry erase calendar earlier. Even on larger boards, these days of the week magnets cover the pre-printed days, and highlight the days printed on the magnets.

Before each performance, you'll use a dry erase marker to write 29, 30, and 31 on the first 3 squares of the 5th week on the calendar, and have the days of the week magnets arranged in the remaining 4 days of the 5th week in the calendar.

When you're given the month and year, write them in the space for the month at the top, and use the Day One technique to determine where to place each day of the week magnet. After placing the magnets, erase any of the last 3 dates as needed (For example: If you're given a February in a leap year, erase the 30 and 31, leaving the 29) and your calendar should be arranged correctly!

After each performance, erase all the dry erase markings, and put the magnets back down in the 4 empty squares of the final week. If you're about to do another performance, write the 29, 30, and 31 back in. If you're not, you can simply put the board and magnets away until you're ready to perform again.

The basic idea of using permanent markers to create a custom design (and knowing how to remove it in case of mistakes), should start the gears turning for other ideas. Starting from a blank dry erase board, you could create things like a grid for a magic square or a chessboard for the Knight's Tour.

The cork-backed ruler I mentioned earlier is an essential when designing grid-based layouts, of course. For the chessboard, I recommend creating the board in a blue that's dark enough to be distinguished easily from the white squares, yet still light enough to contrast with dry erase numbers written in black.

Don't forget that using a magnetic dry erase board can also be a great way to display magnetic playing cards, either in full-size or in miniature.

For one last idea to inspire you, how about a Sudoku grid? You could use it to display your apparent Sudoku genius as taught in Werner Miller's Swindle Sudoku routine!

That should be enough to be enough to inspire you and get you thinking about different ways to customize and present the mental feats you've learned here on Grey Matters.

For my next puzzle, I'll try figure out why custom-printed dry erase Sudoku boards are so much more readily available than custom-printed dry erase chess boards.

I teach quite a few fun mental challenges over in the Mental Gym.

While I teach methods in as simple and straightforward a manner as possible, there isn't always just one approach. In this post, I'll take a look at new approaches to feats in the Mental Gym.

In my tutorial on Squaring 2-Digit Numbers Mentally, I already teach two methods - a mathematical approach, and Jim Wilder's pure memory approach.

NumberSense's approach takes advantage of an algebraic pattern. The number is separated into 2 variables, a being the 10s digit and b being the 1s digit. The problem then becomes (a + b)², whose expanded form shows how to make the problem easier:



Besides making the squaring of two digit numbers easier, this video also illustrates a good point about algebra. Algebra lets you see patterns of which you may not have been previously aware, and help you see a shorter, and possibly better approach.

Another mathematical challenge I tried to simplify over in the Mental Gym was the unit circle and its associated trigonometric functions.

These lessons are especially handy for students taking trigonometry. Here's a handy approach to memorizing the unit circle, especially useful for tests, that works solely by taking advantage of several simple patterns:



We'll wind up this post by focusing on two of the puzzles.

First, there's the Sudoku. I already link to instructions on Sudoku strategy, but if you find those hard to understand, e-How has a series of excellent instructional videos on the Sudoku-solving techniques that you may find helpful.

In the Towers of Hanoi, the seemingly-simple task of moving disks from 1 peg to another quickly gets complicated. Here's a short, direct tutorial that helps make the solving pattern much clearer:



If you've come across an alternative way of doing any of the feats over in the Mental Gym, I'd love to hear about it in the comments!

A good puzzle has the counterintuitive quality of being very relaxing because of the thought you have to put into them. Here's a few good sites to lose yourself in some classic puzzles.

• AMAZING Productions - Just started this month, this is a blog focused on mazes. Each post is a picture of a maze, and clicking on it will enlarge the picture. These are very high-quality original mazes, and should be printed out and given the time they deserve.

• Desert Labyrinth - Do you prefer your mazes in 3D? If so, check out Desert Labyrinth, a simple yet well-rendered 3D maze game that's different each time you play it! The interface is simple enough that it helps keep the focus on solving the maze, not figuring out how to play. You'll probably want to click on the compass to use the overhead view to help. You can even learn about how the game was built here.

• Puzzler's Paradise - If you enjoy logic puzzles that provide you with clues like, “Mary was 2 years older than the person who owned the dog” you'll enjoy this site. You can play online with the interactive grids, or print them out and work them by hand! New puzzles are posted often.

• Jigzone - There's nothing quite like a good old-fashioned jigsaw puzzle. There are several sites out there, but Jigzone has two important qualities over its competitors: 1) The interface is better designed and replicates the feel of the experience, and 2) It works even on devices that don't display Flash. As a matter of fact, the experience is even better on a touchscreen mobile device, since you're grabbing the pieces with your fingers directly!

• Puzzles.com - Looking for a wider variety of puzzles? Then this is the place! From original new puzzles to classics from older puzzle books (including many from Martin Gardner), puzzle lovers should definitely bookmark this site and return regularly.

• Chess and Poker.com - If you enjoy the Mental Gym, you'll definitely enjoy this site. Besides strategy guides for its name sakes, it features guides for everything from Tic-Tac-Toe to Dominoes to Carcassonne! Many classic puzzles are also taught here, including Rubik's Cube, Sudoku, and the 15 Puzzle.

• Jaap's Puzzle Page - This one has been a Grey Matters favorite for a long time. It teaches how to solve a wide variety of commercially available puzzles. In many cases, you can play those same puzzles in online versions, and even share them on your own website! If you want to understand the math behind these puzzles, the site usually gives high-quality mathematical explanations, as well.

Do you have any favorite puzzles sites you'd like to share? Let's hear about them in the comments!

Yes, it's time for February's snippets!

• So, you've mastered the Day For Any Date feat and 40 30s 4 15? Now, you take them both to the next level simultaneously with the 41 Puzzle Mint Calendar! This is basically a 41-piece version of the classic 15 puzzle, prepared as a calendar, and using extra icons that can be used to denote special days.

• I've certainly mentioned plenty of iPhone and iPod Touch flashcard programs to help your memory. However, now there's a memory-helping program of a different sort. It's called Memgellan (iTunes Link), and instead of quizzing you on Flashcards, it helps you develop mental journeys for the Journey and Loci memory systems. You can create and review journeys in this app, which helps you use them as mnemonic hooks later on. Take a look at this video to get a better idea of exactly what it does:



• Do you enjoy Sudoku, but get frustrated when you can't solve the puzzle you're working? Let Excel solve it for you! If you think Sudoku problems are too difficult for a spreadsheet program to solve, then you're in for a surprise. The Microsoft Excel team themselves show you how to do just this in their article Building a Basic, Understandable Sudoku Solver Using Excel Iterative Calculation (Part 1, Part 2). You may or may not be able to adapt this technique to other spreadsheets, since it largely depends on iterative calculations.

• This entry could only be last, because part of it will seem like snippets-within-snippets! Check out Clifford A. Pickover's site. If his name doesn't ring a bell, the best place to start is his About section, of course. However, you should explore the site as a whole. Regular Grey Matters readers will definitely enjoy the Alien Tiles Puzzle and the Reality Carnival. I'm currently reading his Math Book (yep, that's the real name!), which seems to teach me something new everytime I open it!

Have you found anything you'd like to share with Grey Matters readers? Let's hear about them in the comments!

Has it really been 3 full years since I first started Grey Matters?!? It seems hard to believe, but it's true!

I couldn't even imagine back when I started this that Grey Matters would grow as big as it has, and get as many visitors on a regular basis as it has been getting!

I chose today to start the blog because it's Pi Day (3/14)! Pi Day was first celebrated at San Francisco's Exploratorium back in 1988, and it caught on very quickly. Let's kick off this celebration by checking out the Exploratorium's plans for Pi Day 2008, which includes ideas you can try at home.

Even though, as we've discussed in the past year, you'll never realistically need more than 40 digits of Pi, the challenge of refining Pi to more and more digits is often too much to resist. It's why we do things like memorize hundreds of digits of Pi, and even calculate it out to more than 1.2 trillion digits (1,241,100,000,000 decimal digits of Pi, to be exact)! If you want to explore the digits, you can download pre-calculated digits, or have your computer calculate the digits in real time (Mac OS X version and Windows version).

As fun as pure lists of Pi digits can be, it's much better to get an understanding by putting them in context, as in my aforementioned Visualizing Pi post. You can use Wolfram's new Mathematica Player to examine Pi in context. First, you can easily examine the distribution of digits in the first 10,000 digits of Pi, even in numerous bases. This is great for seeing how long before, say, a 0 appears, or finding the Feynman point. If you've ever wondered why Pi is the value it is, try out this demonstration to see how various shapes relate to their respective circumferences.

However, we're here to celebrate and have fun! Here's an unusual pi-themed Sudoku puzzle to challenge your brain. Instead of a standard 9 by 9 Sudoku using the numbers 1-9, this is a 12 by 12 Sudoku in which each row, column and region (most of which aren't rectangular) must contain the first 12 digits of Pi (3.14159265358). The three 5s two 3s and two 1s add a new dimension of challenge to this puzzle. For a little more passive fun on Mac OS X 10.4 or greater, check out the Pi Viewer and Pi Clock Dashboard widgets. For some more passive Pi fun on any platform, how about the now-classic Hard n Phirm Pi song:

If you're not looking for just the digits, you can go to this video or this website.

Don't forget! It's also Einstein's birthday today! If you'd like to celebrate Einstein's life and have some fun, learn a little bit about his relativity theory over at Al's Relatavistic Adventures and EinsteinLight.

Don't forget to look around Grey Matters and explore all it has to offer, such as the all the Pi posts I've made. Maybe you'll find an entirely new section of the site you didn't know about before! I've enjoyed these three years, and I hope you've enjoyed the ideas and posts I present. Here's to another year of Grey Matters!

Plenty of cell phones can access the internet, but the iPhone and the iPod Touch have already seemed to capture the attention of the phone and wi-fi public. What are the options for those who want to tease their brain with an iPhone or iPod touch?

I've already started work on a new section for the Mental Gym, called the iPhone Mental Gym. At this writing there are only two items in it, Albert Omoss' Sudoku, and my own original Knight's Tour. This version is a special adaption of the Knight's Tour at the Mental Gym, where you can also learn how to do the Knight's Tour.

If you don't have an iPhone, you can try them out online. If you want a fuller iPhone/iPod Touch experience, you can also try out TestiPhone. Just type http://www.testiphone.com/?url= and the web address in your browser's address bar, and try out your own online iPhone! For example, typing http://www.testiphone.com/?url=http://members.cox.net/astonishment/iphone/iknightquiz.html, and you'll get this as the result.

These two aren't the only way to challenge your brain, of course. Want to perform the 40 30s 4 15 feat? First, learn how to do it, and then use stephan.com's iFifteen.

How about a calculator for feats like the root extraction feat? Since numbers for many mathematical feats can become large quickly, I recommend Garth Minette's Belfry SciCalc (TestiPhone version).

I don't want to completely rob you of the joy of discovery, however. Start by checking out AppSafari and iPhone Widget List, and do a little exploring.

Yes, normally I post my blog entries much earlier in the day, but I've been distracted and fascinated by the subject of today's post, the Wolfram Demonstrations page.

Back in May, Wolfram Research released the newest version of their classic software, Mathematica 6. Of the numerous new features, one of the most eye- and mind-catching is the ability to export to their new notebook format (.nbp).

What is notebook format? Short description: It's like QuickTime player for mathematical demonstrations. Long description: It's a special file format that allows users, via the free downloadable Mathematica Player, to manipulate interactive mathematical demonstrations. Those who have Mathematica 6 can develop their own original demonstrations.

There are already over 1700 free downloads available on the Wolfram Demonstrations page, and more are being uploaded every day. The best place to start to give you an idea, while having some fun at the same time, is the puzzle section. You can try everything from the classic puzzles, like Towers of Hanoi and the 15 puzzle, to more modern puzzles, like Sudoku and Planarity.

From here, you can look through random demonstrations, search or browse by topic (via the menu). If you've enjoyed some of my mathematical discussions in the past, such as the Monty Hall Dilemma (demonstration), Buffon's Needle Problem (whose demonstration is cleaner than the frozen hot dog approach) and Prisoner's Dilemma (demonstration), you can now experiment with them more directly!

For the fullest experience, I suggest trying out the demonstrations that interest you, and do further research on those topics in Wolfram's MathWorld section. Which reminds me, I've got to get back to these demonstrations myself!

Attention, Carnival of Mathematics fans! The 12th Carnival of Mathematics is up over at the Vedic Maths Forum India Blog!

Regular Grey Matters readers will especially enjoy the entries on Sudoku and graph theory and mnemonic abbreviations.

Sure, there's plenty of puzzles and challenges over at the Mental Gym, but for those who seek further brain-straining, even more await out on the web!

I'll start with the more familiar puzzles. If you'll fire up your computer's or browser's Java Virtual Machine, we can head over to MazeWorks. This site features many classic puzzles, such as the 15-puzzle and the Towers of Hanoi, along with many new puzzles you may enjoy discovering.

Let us not forget the humble logic puzzle. How about starting by trying to get our hero a kiss from a pretty girl? If that's not enough, and you can keep from peeking at the answers, here's 13 more puzzles for you to solve!

If you're a fan of Sudoku, you can head over to the Mental Gym's Sudoku page. However, if you wish to delve deeper into the nature of the game, see what happens when sudoku and mathematics intersect.

Understanding the principles behind the puzzles may or may not help you solve them, but it will help you understand the nature of the puzzle itself. This can even help you create new puzzles. As a matter of fact, Maki Kaji, the father of Sudoku, has used similar principles to create a new type of puzzle called Masyu (PDF, will open in new window). If you want to try this Masyu puzzle for starters (PDF, will open in new window). Don't worry, there are already plenty of Masyu puzzles available on the web if you get hooked.

Oh, and if you need any help solving any of these puzzles, take some advice from Square One TV's Larry Cedar:

There have been a few changes being made to the Grey Matters site, so I thought I would keep you posted.

First, the video index is no longer in the rightmost column. Don't worry, it still exists! Under the Video section, you will now see a new link that says Full Video Index. Having the link in one place has already proven to make Grey Matters Videos far more manageable. As before, the Full Video List will constantly be updated as I come across new videos.

Also, there are now more challenges in the Mental Gym! Besides the classic challenges that are taught on this site, these new challenges each include links to off-site solutions. For example, the new 15 Puzzle section (Java required) links to these instructions, as well as my magic square variation.

Besides the 15 puzzle, I've also added Simon (Flash 8 or better required) and Triangular Peg Solitaire (Flash 8 or better required). As time goes on, more challenges will be added.

Finally, over in the Presentation section, I've added the Made To Stick Blog. This blog is run by Chip and Dan Heath, the author of the book of the same name. The basic idea behind the book and the blog is to show what qualities an idea must possess to become easily memorized and passed on. The authors use Malcom Gladwell's concept of "stickiness" to describe the effectiveness of a given idea.

Enjoy, look around, and explore these new sections!

Philemon Vanderbeck has a new school show called Arithemagic. As you might guess from the name, the focus is on present AND teaching math-based effects.

To get an idea of the show, I suggest checking out the video (play along!) and photo sections.

When performing his school show, Philemon also gives teachers NINE, the lecture notes for the effects taught in the show. These lecture notes are also available for purchase, for $9, of course. As far as the effects themselves go, most of them are classics of mathematical magic, and I've discussed many of them on this site, such as extracting cube roots and fifth roots or the Fibonacci addition trick.

A quick look at the table of contents (PDF) might lead one to think that the notes aren't worth purchasing just because they're classics. However, there are some gems here, such as Werner Miller's Swindle Sudoku, as well as some impressive presentations. NINE has a great presentation for the old 1089 trick. As a matter of fact, NINE and Hidden Numerical Forces are the only two resources I've ever found with engaging presentations for the 1089 trick.

It's great to see math and magic being presented in such a positive and fun way to school students. Teachers and school administrators from Washington state should especially check this site out, but that shouldn't stop others. Anyone interested in mathematical magic should check out this site, as well.

It feels like a lazy weekend, so today, we'll just relax with some pleasant mental diversions.

Let's start off with 50 States in 10 Minutes, in which you have to list as many U.S. states as you can in 10 minutes.

Less challenging, yet equally puzzling, is Fido's Mind Reading (Flash required). Like these mind reading feats? You may also like Andy Naughton's Flash Mind Reader (Flash required).

Is your brain still hungering for more? Check out Google's Puzzle Gadgets for a nearly endless supply of mentally challenging puzzles!

Have you ever opened up a new deck of Bicycle Playing Cards and seen the card featuring a Sudoku puzzle?

It's meant as an ad for the Bicycle Sudoku puzzle deck. Imagine, when someone opens a deck and finds such a card, that they hand you the Sudoku card, you take a brief look at it, and then hand it back, rattling off all the numbers from left to right and top to bottom!

One interesting thing is that the demo puzzle is always the exact same puzzle, the one pictured in the upper left corner of this article. With that little bit of knowledge, this pseudo-memory feat becomes much easier.

First, you need to learn the Link System and the Peg System. Once you're comfortable with those methods, you just need to learn the following paragraph by heart:

"Jay Leno, our Honda issue: My wheel may err. No good paved. Bike error? Bashed notch off Park Avenue, hit oil well here."

This sentence translates into the numbers from the puzzle! Here's how the phrase breaks down with the corresponding numbers in parentheses:

"J(6)ay L(5)en(2)o, our(4) Hon(2)d(1)a iss(6)ue: M(3)y wheel(5) m(3)ay err(4). N(2)o g(7)ood(1) p(9)av(8)ed(1). B(9)ik(7)e err(4)or(4)? B(9)ash(6)ed(1) n(2)otch(6) off(8) P(9)ar(4)k(7) Av(8)en(2)ue, hit(1) oil(5) well(5) her(4)e."

One you're practiced in both the mnemonic systems and the above phrase, you'll have a feat you can perform as either a psuedo-memory feat, or a divination feat!

Werner Miller is a retired teacher of mathematics, whose hobbies are recreational mathematics and magic. His unusual and amazing approach to magic squares were mentioned in this blog in June, 2005. Now, he's turned his attention to Sudoku.

Imagine the reaction you'll get when you have someone generate a random Sudoku puzzle, which you're able to solve in less than a minute! While you're getting credit for a staggering mental feat, it's actually much easier than it would otherwise seem, thanks to Mr. Miller's Swindle Sudoku. This ingenious routine would work well as an opener, as Werner Miller puts it, “to lay the foundations for your reputation as a mental prodigy”. It's also flexible enough to work on anything from a simple blank Sudoku grid on paper, to physical Sudoku boards, such as Rubik's Sudoku or this Deluxe Sudoku Game Board.

If you like Werner Miller's way of mathematical magic, you can also check out his other original effects at Online Visions, or buy his first collection of effects in English, called Ear-Marked.

As you've probably guessed from the previous two entries, I'm in somewhat of a do-it-yourself mode lately. Naturally, this led me back to instructables.com, which has grown radically since I first mentioned the binary counting HowToon back in October, 2005.

I'm glad I went back, because I've found more great projects of interest to Grey Matters readers.

First, there's the method for solving Sudoku puzzles without thinking. Personally, I prefer the method taught in How To Solve Every Sudoku Puzzle, but the instructables method does work. Either way, you can practice your Sudoku skills at the Grey Matters Mental Gym!

No, Rubik's Cube fans haven't been forgotten. You can find ways to make a clear magnetic Rubik's Cube, or simply “pimp” your existing Rubik's Cube.

Finally, for fans of the classic Simon game, there's an awesome interactive drumming game based on the same idea. If you want to see what this looks like when it's completed, check out the movie (Quicktime required) of the drum game in action.

Thanks to the hard work of the folks over at Bin-Co, I've just updated the Sudoku page over in the Mental Gymnasium. There are plenty of new features in the 2.00 version, including:

Hard/Normal Levels of play

The Pen feature

Invalid items will be show in another color - ie. if the user enters two numbers, it will be shown in a red colour - so that the user still remembers to change it

A hint system - the users will have an option that will warn them about a bad move(repeated numbers) right after they made the change. For example, the user will enter 7 and the script will give a warning that 7 already exists in the vertical row.

Save chosen style and reload it at startup.

Reveal any one cell at users choice.

'How am I doing' Option.

Timer

When a value of a cell is reveled, it fades into view.

The status text under the game is hard to notice. Added a Fade effect.

Font size become smaller if multiple numbers are entered - for keying in the possibilities.

A more printer friendly format.

Counter starts when the puzzle is shown.

I hope you enjoy the new version, and I wish you happy solving!

If, like me, you've been driven to distraction and near-madness by Sudoku, you've probably been looking for more effective methods for solving the puzzle.

I'm glad to say that I've finally found an approach for Sudoku that suits me. If you've been to my Mental Gymnasium, you'll know that I like approaches for mental tasks that are simple, straightforward, and minimize the number of mental constructs required to perform them.

There is just such an approach for Sudoku taught in the How To Solve Every Sudoku Puzzle ebook (PDF, 121 pages) by Harvey Intelm. The first 5 chapters in this ebook cover the basics of Sudoku, as well as the history, benefits and interesting facts of this popular puzzle. Chapter 6, however, is where the real lessons in Sudoku-solving begins.

First, Mr. Intelm introduces a simple standard notation that will be used throughout the rest of the ebook. Next, he does something that makes the rest of the learning much easier. A simpler version of the Sudoku board is described, and used to teach the basic ideas in this solution method. Progressively more complex approaches situations are described in this simplified board, so that you quickly and easily get the techniques down, and understand what kind of situations you may face.

Altogether, there are only four simple techniques taught. With practice, these become relatively simple to apply. Next, these four techniques are arranged into a 7-step process. The simple 7-step process that is taught has a number of advantages. First, the simpler the puzzle, the fewer steps you'll use. Second, if a puzzle is so poorly constructed that it has multiple solutions or even no solution, this approach will let you know. This is how the author is able to claim that he can teach anyone to solve any Sudoku puzzle.

After giving some simplified Sudoku puzzles on which you learn various aspects of the procedure, the author then shows you how to apply what you've learned to normal Sudoku puzzles. The remainder of the book compares the various approaches to solving the puzzles, discusses the merits of computer-assisted solving, and links to Sudoku and Sudoku-related puzzles.

In an earlier entry about Sudoku, I did link to a page describing Sudoku-solving techniques. However, these techniques are never put together in a cohesive framework (at least, in any reference I've ever come across), which can make these techniques frustrating to learn and use.

If you like the approaches I've used in teaching the feats in Grey Matters Mental Gym, I think you'll also appreciate this ebook's approach to solving Sudoku puzzles.

Speaking of the Mental Gym, I'd like to take this moment to announce that, thanks to the good graces of Bin-co, I have now added randomly-generated Sudoku puzzles, which you can solve online, to the Mental Gym, and they are accessible via the workout page!

Yes, Rubik's Sudoku is a real thing, or at least it will be soon. The question marks are in the title of this post because there's no word on the official Rubik's site about this product yet. I'm not even sure exactly what this thing is.

Doing some digging around the web, here's what I've found. Funagain Games is the only US supplier I've found for Rubik's Sudoku. Over in the UK, Amazon.co.uk's listing for it is already up.

It seems to be some kind of Sudoku visualizer, built by Rubik's that comes with a book of 100 puzzles of it's own, and can be set up for any other Sudoku puzzle, as well. It's expected to be released in May, 2006. From the descriptions, you can use it both in the "normal way" (apparently with all tiles being the same color), or with colored tiles, to help you visualize possible solutions better.

As soon as more information is available on this new mystery item, I'll provide an update.

It's tough enough finding sites that encourage you to strain your brain, so when I find such sites that, like Grey Matters, believe this should be fun, then you know I'm going to post them right away!

Our first stop is Gloo: the memory company. This is the site for an Australian company that focuses on improving memory. Like me, they have a passion for fun and mental improvement. On their site, you can find not only their services, but plenty of free stuff, as well! First, they're one of the sponsors of the World Memory Challenge, which I mentioned in this blog last December. They also feature a free newsletter called, “Splat!”. Many of the back issues are available on their site with a little hunting (including the editor's record-breaking Pi memorization), but you can also subscribe to the newsletter via e-mail. When you sign up this way, you get a free bonus, an article called, “How To Remember 'Whatshisname'”. It's a short but informative article on how to improve your memory for people's names. If you've ever had this trouble, sign up for the newsletter and get this article now! Take a look around at their other free goodies, as well.

Our other stop today is Braingle, a site so large, I'm not quite sure where to begin. This is a free membership community where you can join in with others who like to stretch their mental capacity. Braingle's 5 main sections are Brain Teasers, Mentalrobics, Games, Community and Store. The parts of the site that mainly captured my attention were the Mentalrobics articles, especially the memory articles, the flash card section and the puzzles. Their Java-based 15 puzzle is great for praticing the “40 30s 4 15” feat. Yes, of course they have Sudoku (Flash required), as well.

Have fun looking around these sites, and I'll be back on Pi Day!

Being a Mac user and programmer myself (which you may have figured out when I released the Grey Matters Dashboard widget), I've been looking at various free brainteasing programs for Mac OS X recently, and I thought I'd share my findings with you.

Plasq, a Mac software development company best know for their Comic Life software, has just turned 1 year old. In celebration, they're giving the gifts! The gift they're giving is a free version of the classic 15 puzzle, called Pluzzle. As a whole, this is very nicely put together. The look and sound (yes, sound) is that of a puzzle made out of wood. The tiles actually make the sound of wood scraping against wood when they're moved. The puzzle itself can be set to any size from 3x3 to 7x7, and photos can be dragged and dropped into the puzzle to be used as the background. If you've taken the time to learn my "40 30s 4 15" feat, this is a pleasant way to practice.

Thanks to the Dashboard feature in Mac OS X, there are plenty of free brainteasing widgets now available. One of the most original and challenging widgets I've come across is Cross Eyes mini. You have to keep the eyes from making angry stares at each other by separating each pair of eyes that are the same color.

There are also many versions of classic puzzles and games available, as well. You can find versions of Rubik's Cube, Sudoku, Mastermind and even Concentration.

Although they're not brainteasers in the classic sense, I have found several guilty and geeky pleasures available as widgets, as well. There's Jumbolaya, which helps you solve anagrams by allowing you to visualize new possibilities, and the Einstein Random Quote Generator. However, anyone who knows me will understand why the closest one to my heart is this one. No, it doesn't do anything except sit there, but that's enough for me.

I don't mean to belittle the brain challenges available on the Windows platform, but as I work more with the Mac, I have to go with what I know.

Judging by the 'ol BallClock on the Dashboard, it's time for me to be going now.