I've recently discovered quite a few links related to recreational mathematics that I'd like to share with you!

1. When talking about the day of the week for any date feat before, I've usually focused on the classic mnemonic version. However, there is another approach to finding the day of the week for any date, called the “doomsday” method. While I've run across this method before, this link goes to one of the clearest step-by-step set of instructions for the doomsday method that I've ever seen.

2. Archimedes' Laboratory is an Italian site filled with puzzles, games, brain teasers and more. Readers of this site will especially be interested in the Curiosities section, and the Archimedes' Laboratory store.

3. Do you think you've seen it all when it comes to recreational mathematics? You can't really say that, at least not until you've visited Ian's Shoelace Site! Until I found this site, I never even considered that there was more than one way to lace shoes, much less that there are 1,961,990,553,600 ways to do so! As I am a big fan of whimsical applications of mathematics, this one struck me as soon as I found it.

4. Just to give you an idea of the amazing applications of math that are out there, check out Knot A Braid of Links (KaBoL, for short). This is a directory of math-related links that has been in operation since 1996. Naturally, some of the older links have moved or been discontinued, but there are still many interesting functional links.

5. Speaking of lists of links, I am in the process of updating my list of affiliated CafePress stores over in the Grey Matters Online Store, so please stop by and check out the new links!

The big news I promised in yesterday's post is now ready for release!

Have you been thinking about purchasing my Train Your Brain and Entertain memory training software, but have been hesitating due to the shipping charges or concerns about the security of the Grey Matters Online Store? I have an alternative for you now!

This is because both the Mac OS X version and the Windows version of my program are now available from Murphy's Magic Supplies!

Murphy's only sells wholesale, and not to the general public. However, almost every magic dealer orders from Murphy's, so you can most likely ask your favorite magic store to order it for you, just as with most other magic routines.

You can read the description of the Mac OS X version or the Windows version, if you aren't familiar with it. If you have the Flash plug-in installed in your browser, you can also see the Mac OS X slideshow and the Windows slideshow!

Update (5/25/06): My CD-ROM is already available through Hocus-Pocus Magic, where members can get US$5 off!

Word is starting to spread about my Train Your Brain and Entertain software (TYBE)!

In addition to LobowolfXXX's Magic Cafe review, there's another new review at MemoryMentor.com (Mentioned on this blog here and here)!

This is especially good timing, as I'm expecting to make another big announcement soon about TYBE. No, I'm not giving any hints yet.

I'm honored that Kevin chose my software to be included in the opening of his brand-new review section. Besides my software, he also reviews several books, including a brief review of Dominic O'Brien's classic work on memory. He mentions that you may need to search eBay, but it's available as an ebook from Lybrary.com, as well.

Every act should have style, even a memory or mental math act. I recently ran across some nice items at Brookstone that can do just that.

First, we have the 100-Year LED Calendar, which is perfect for the classic “Day of the Week for any Date” feat. This is a digital calendar that allows you to scroll backward and forward to see the calendar for any month and year, within a 100-year range. There's also a “Home” button that allows you to instantly return to the current year and month. These buttons could easily be used to allow and random month and year to be selected, simply by letting the spectator push the back and forward buttons until they're satisfied that a free choice has been made. This calendar is also big enough and visible enough for a parlor routine, or even a small stage setting.

Speaking of big enough for a parlor setting, there's also the Supersize Pop-Up Calculator. As you can see by the paperclips that were included for scale, this thing is BIG. Your average four-function checkbook-style calculator is only slightly larger than each of the buttons on this calculator! No one in the first few rows will ever challenge your mental calculations again, as they can easily verify the sums on this calculator, even if someone else is verifying the answer.

If your tastes in calculators runs to a more normal scale, you may prefer the Color-Changing Calculator, instead. While it can be used in a normal grey-and-black mode, you can also set it to a backlit mode, in which the color of the backlighting changes every time you enter a number or function. This not only makes the numbers easy to see, but helps add a fun element to mental math demonstrations, which is always welcome.

Yes, I am a little busy due to this being Mother's Day, but I do have some quick tidbits to share:

* Over on Penguin Magic, I have an instant download for sale called, “The Sweetest Sound”. I was flattered recently when I ran across B. H. Bowhunter performing his version of my effect over on YouTube. Good job, B. H.!

* When reviewing the book, “Act Two”, I briefly mentioned the Trachtenberg Speed System of Basic Mathematics. If you're at all curious about this, I've found some great links on the web, here, here and here that can help you understand the basics.

* Would you find anywhere from US$30,000 to US$605,000 useful? Do you like math? If so, head over to the RSA Challenge Number page. All you have to do is "simply" to factor the numbers they give you on the site, and collect your reward! Oh, I should mention that the smallest number on the site is 212 digits long.

After adding the video menu, as mentioned in my previous post, I realized that, without descriptions, there wasn't much reason for anyone to look up a particular video.

To fix this, I've added a whole new video blog to Grey Matters! Instead of a traditional video blog, where I would be filming myself stating my thoughts, this blog is more of an archive. The first post can explain in more detail.

Much like the main Grey Matters blog, Grey Matters Video has its own RSS feed (also accessible under “Site Feeds” over on the right), categories and archives. If you want to suggest any videos that you think belong there, suggest the video in the comments box of any post in the Videos section.

I admit, with an unusual interest such as memory and math feats, it's not always easy for people to communicate how impressive these feats can be.

To help that situation, I've added a new feature to Grey Matters. If you look in the rightmost column, between “Downloads” and “External Links”, you'll find the new “Videos” menu! I've posted links to videos here and there, but this is the first time I've had a regular place to include them on the blog.

They're divided up alphabetically by video format, which currently includes Flash, Google Video, QuickTime, Windows Media and YouTube, and then alphabetically by the last name (or only name given). Each of the video format headers will take you to a corresponding page where you can learn more about that format, and download any files required to watch them, if needed. Please keep in mind that, while most videos will play in your browser, some will download and run in a player.

Currently, there are 40 different videos on the list, but I hope to expand the video list in the future. Some are people who've practiced their feats, while others are savants who perform their feats with little or no practice. Among the highlights are Scott Flansburg's appearance on Oprah (“Scott Flansburg 1”), the man who was the inspiration for the movie Rain Man (“Kim Peek”), and a man whose memory earned him over $110,000 on a game show (“Michael Larson”). There are more, but I won't rob you of the joy of discovery.

Also, if you have any video of amazing mental feats that are hosted elsewhere, please let me know (click the “Contact Me” link at the top of the blog), so that I may review them for possible addition to the list.

In the meantime, enjoy the videos!

This month's (May 2006) Genii Magazine features some great routines that will be of interest to readers of this blog.

First, there's Harry Lorayne's To-And-Fro Magic Square. This is a simpler magic square routine, quickly generated with any four numbers chosen by the audience. It's a simpler routine good for a point in your show where you need a simpler, more relaxed effect. It would also be great as a lead-in to a more complex and impressive magic square routine. You can find this routine in the Mathematical Wizardry book, as well (You can find my review of this book here). Just over a year ago, Genii published another magic square routine, called 4x4 Magic Square Breakthrough??, which is a more involved routine that is worth looking up.

Next, there's Seven, by Roberto Giobbi, who is best known for his Card College books. Seven is a card routine which he taught at the recent "Gathering for Gardner 7" (G4G7, for short). It's a self-working, mathematical routine in which you openly predict where a selected card will wind up, despite the audience determining how much the cards are mixed. It's a great variation of Gary Plants' routine, A Four-tunate Choice, from the September 1997 issue of Genii. As this routine is intended for an audience that isn't entirely magicians, there are some handlings that are almost too simple for the professional and amateur, but even the author acknowledges that Genii readers will quickly recognize where changes can be made to it.

The final routine I'll mention from this month's Genii isn't necessarily a memory- or math-based effect, but it is interesting nonetheless. Bob Farmer's Flim-FlaMagic column this month describes a routine called, One Faces South (Parodying the now-classic routine title, 51 Faces North). You show a paper depicting 51 cards face-up, and one card face down, and explain that there are 3 ways to discover the identity of the card - Have the performer reveal what it is, look at the other 51 cards, and use logic to determine the missing card, or through the use of an trans-cranial, intergalactic telepathic mind meld. Guess which one Bob Farmer proceeds with?

The spectator shuffles the deck, and then proceeds to recreate the situation shown in the picture that was just displayed. They deal out cards face-up in a circle, dealing a face-down card that is unknown, even to themselves, at any point. Any remaining cards are used to complete the circle. At this point, the magician brings the drawing back out and reveals the identity of the face-down card. To prove it, the spectator is asked to find all the cards of the same value in the picture. Naturally, only three of them can be found, confirming the identity of the face-down card in the picture. The face-down card that was dealt onto the rest of the deck is turned up, and shown to match the predicted card!

This is a great routine, and is well thought out, with a great synthesis between method and effect. If you are interested in performing One Faces South, however, you will need to make sure you have access to the February, March, April and May 2006 issues of Genii (ahh, these crafty magazine editors!).