Yes, you read correctly. Over the past few days, I've added 2.5 items to my line of goods over at the Grey Matters Online Store.

I guess I should start by explaining the ".5". Back in March, I originally released the Day For Any Date 2006 Calendar. As noted in the last paragraph of that article, once you purchased it, you had to contact me for the secret itself. To improve the method of learning, I've re-released the Day For Any Date Calendar with an instructional booklet, so you can learn how to use the calendar as soon as you receive it! You can, of course, still contact me if you have any questions.

The other two items are purely for fun.

First, there's the “39” Magic Square Postage Pal™, which come as a sheet of 20. For those not familiar with Postage Pals™, these are fun stickers which go on an envelope, and then the stamp itself goes on these. They started out as a way to donate charity, but have become more and more popular in recent years as a means of self expression. Since standard stamps in the US are currently 39 cents, I've designed one (pictured above) that includes a magic square that totals 39 in many different directions. You can explain this in the note you send, or just let 'em wonder.

The last remaining item is my Back Scratching shirts. While these don't have much to do with math or memory, I though this was a fun idea. Ever have an itch on your back that you can't scratch yourself, and you have difficulty explaining exactly where that itch is to someone else? This is my answer! On the back of this shirt, there's a grid with columns marked A-J, and rows marked 1-10. You can give the coordinates to someone else, and they can scratch exactly in the right spot the first time!

But, if the grid is on the back, how do you know the correct coordinates to give? Simple! There's an image of the shirt on the front, oriented so that the wearer can look at it correctly, and find the needed coordinates quickly.

If you like these, or any of the other items at my online store, don't forget that you can make 20% of the price for yourself by helping sell through the Grey Matters Affiliate Program!

This concludes our commercial message, and we now return you to your regularly scheduled blog.

The London Times, in honor of the 300th anniversary of Benjamin Franklin's birth, has posted a challenge to their readers. The object is to complete this magic square, which was originally designed by Ben Franklin.

If you're not sure where to start, they do offer some helpful hints. Of course, searching this site for the phrase “magic square” may also prove helpful.

I just received the following e-mail, and I am republishing it here with the permission of the sender, who asked to be kept anonymous:

Hi there Scott, I just wanted to tell you thank you for your wonderful site. Currently I'm working on a mentalism/hypnosis show that I will be doing for free for a charity for Katrina victims, and I'll be incorporating your lesson on the Knight's Tour as a publicity stunt for the local chess club to try and sell more tickets.

I've gotten to the point where I can do it without seeing a board and just doing it in my head, so I'll have several of the local chess experts do their best first while looking at a board (and hey, if they make it, they are chess experts, after all. No big wupp.)

I'll then be blindfolded and do the Knight's Tour with no board to look at, and surrounded by chess club members who will make sure I am not using a crib sheet.

This should be good. This should be so freaking good. Afterwards, donations will be collected, and tickets to my charity show will be sold.

Thank you so much! I couldn't have done it without you!

You're welcome! While I put this site together because it covers my own particular interests, it's nice to hear that others are not only using the information on here, but making a difference with it, as well!

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!

Even though the Grey Matters Online Store has only been open for a few months, it's already doing better than I initially expected.

As a way of thanking you for your support, I am officially announcing the Grey Matters Affiliate Program!

You start by signing up for the CafePress Affiliate Program. Once you've done that, simply include the banner link code on your website or blog, or the text link code in your e-mail or discussion board post. When someone clicks on the link and makes a purchase, you receive up to 20% of the retail price (less any discounts) as a reward (see the above CafePress Affiliate link for full details).

If you have any questions about the affiliate program, contact me either in the comments section of this post, or by clicking the "Contact Me" link at the top of this page.

Jim Steinmeyer has released a sequel to his popular Impuzzibilities book, entitled Further Impuzzibilities, which are availble from most magic dealers, as well as directly from Jim Steinmeyer.

Jim Steinmeyer, for those who don't know, is one of the biggest names in illusions design. If you've ever seen a magic show that included any of these routines, you'll have an idea of just how original and creative he can be.

Both of the books in the Impuzzibilities series, however, are not illusions, but rather simple impromptu effects, many of which can be done over the phone! Impuzzibilities itself opens with “The Nine Card Problem”. As with many of the effects in this series, this is one of those effects that will fool you while you're doing it. This one has even been performed on David Copperfield's “Passions of Fire” special. The routine that follows, “The Full Deck Problem” expands the principle, and can be performed even if the deck you use is missing cards.

”Dime and Pennies” and “A Quarter to Nine” were a joy to discover. These routines use a radically new dressing for a very old mathematical principle. Even those posted on the classic principle may not catch it in these new guises. In both routines, you have someone get out a handful of coins, and ask them to take how much money they have, and then subtract the number of coins from that amount. You are then able to predict something about the total.

Moving from cards and coins to clocks, we have “The One O'Clock Mystery”, “The Three O'Clock Mystery” and “The King Mystery”. In these impromptu effects, you're able to predict where a spectator will land on a clock face (or other similar circular arrangements), despite an amazing freedom of choice by the spectator. The principle behind these pieces is also used in commercial effects, such as Eric Maurin's Watch Crystal.

”Understanding the Bermuda Triangle” is Steinmeyer's new dressing for an effect that has been performed longer than almost any other effect except Cups and Balls. In this routine, you arrange small paper airplanes in a triangular formation, and count them out, so that you know that all sides of the triangle have exactly the same number of planes. Despite more and more planes being added to the triangle, you can show that the number of planes remains quite constant.

The next four routines in Impuzzibilities all feature a gambling theme. Here you'll find new routines for the venerable Ten-Card Poker Deal and Monte-type effects. The “Three Card Monte” routine here deserves special mention. When performing this one over the phone, the person for whom you're performing will truly not know where the card is, yet you can control its location.

The first book in the series closes with “Teleportation”, an ingenious idea that allows you to magically and impossibly move a single card from one pile to another, even when performing this over the phone! Performed properly, this can be very effective and get a great reaction from your audience!

The new sequel, Further Impuzzibilities, starts with two routines based on the same principle, which allow you predict the outcome. In “The King's Coronation”, an audience member arranges the four Kings in their hand, and then eliminates them one at a time, yet you are able to determine which King is left. If you like this type of routine, but didn't bring your deck of cards, “Automatic Palmistry” is the answer, as this version of the routine requires absolutely no props!

”Princess In A Crowd” is a routine in which you divine the location of a mentally chosen card among a group of 15. This one reminds me a little too much of the hoary 21-card trick, but the presentation is much more streamlined.

In “Coins in a Strange Land”, “Piles of Money” and “Five Cards on the March”, a principle originally created by Stewart James is applied to cards and coins, giving you a very clean way in which to determine the outcome of choices made by the spectator. The best of these three, in my opinion, is “Piles of Money”, as the handling appears the most carefree of the group.

If you would like to be able to determine a word chosen from someone else's dictionary, even when done over the phone, you may enjoy the ingenious “Lesser Dictionary Test”. The freedom allowed in making the choices is quite startling, but I've never really cared for book tests in which random numbers are chosen and had mathematical operations performed on them. Having said that, the principle used in this routine could be adapted to more effective uses, so it's still worth a look.

Those who enjoyed the “Ten Boys Poker Deal” from Impuzzibilities, but prefer the game of “21”, will be glad to see the “'Five Fiends' Play Blackjack” routine. This is a three-phase routine in which the performer repeatedly deals two Blackjack hands and wins by a very small margin. For the finale, the performer uses all the cards to reach a perfect 21. If you enjoy routines like “Ten Boys” and “Five Fiends”, I recommend getting Stack Attack for a deeper examination of the principles behind these routines.

The last two routines are a wonderful example of saving the best for last. “The Great Silverware Scam” is a rarity. After all, how many routines can you name that are flexible enough to be done in a stand-up, stage or close-up performance, AND yet can still be done over the phone? This is a variation of the venerable Piano Card Trick, but it's done with silverware to add a touch of universal experience to the routine. Michael Weber has a similar presentation with socks that you may want to try and find, and which also has some added work that you may be able to apply to this routine.

Finally, we come to “The Thirteen Card Dilemma”. As written, this is simply a whimsical counting demonstration with playing cards or business cards. There are three phases. In the first, you start with 13 cards, and, despite the fact that you're removing cards one at a time, you keep winding up with one MORE card each time. In the second phase, you add one card at a time back to the pile, and yet the result is that you have one card LESS. The final phase starts with the removal of two cards from the pile, yet the same number of cards remain in your hand. Two more cards are removed, and sure enough you still have the same amount of cards in your hand. The conclusion of the final phase happens when you add two cards, and actually wind up with two more cards, which then suddenly disappear when set in the spectators hand!

There are several great things about this routine. First, there is no sleight of hand required. The false counts in the routine are mathematical, and require practice so that you know how to apply them at each stage. My favorite aspect is the nature of the routine itself. You aren't trying to convince your audience that you're really counting the cards properly each time. They understand they're being hoodwinked, and probably even understand to some degree how they're being hoodwinked, yet they are amazed at the variety and flexibility that is possible with the nature of the scam. The fact that they count the cards themselves to verify that the number of cards you claim is correct helps heighten the amazement.

Having said that, the presentation as written will probably be ignored by the magicians who read this book, as it can seem a little silly and meaningless. However, while talking with Lew Brooks and Will Gordon, both of whom you may know from the Stack Attack DVD, we have managed to come up with an excellent presentation for this. Instead of playing cards, our idea was to use bills (preferably new, crisp bills, in order to make the handling easier), and talk about the dangers of smooth talkers who use their wit and charm to separate you from your money in various ways. This presentation actually works with the nature of the routine I described earlier, and strengthens and focuses the routine in the audience's mind.

All in all, I highly suggest getting both Impuzzibilities and Further Impuzzibilities for not only the included effects themselves, but also for the inspiring nature of the routines, as well.

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!

Here's something you don't see often - a new, original memory demonstration! I came up with this idea while reading Mental Floss magazine, in which Jeopardy champion Ken Jennings has a column in which he's challenged to link two different concepts together in less than 6 degrees of separation, such as linking Kevin Bacon to Canadian Bacon, or Eminem to M&M's. If you're not familiar with the basic “6 degrees” concept, this Wikipedia article will explain further.

My concept for this feat is as follows: You have 10 cards, each with the name and/or photo of a particular movie celebrity on them. These are dropped into a bag, and two of them are randomly chosen (no force!). The performer is then able to link one actor to the other in a minimal number of “degrees”! The performer points out that there are 90 (10 * 9) different ways the first two cards could have been selected, and that they will repeat this feat with two more randomly selected celebrities, raising the possible combinations to over 5000 (10 * 9 * 8 * 7 = 5040) potential combinations!

I don't have a definite closer, but I was thinking that you could close by having all but two of the remaining names read off, and you correctly identify the two names not given AND link them together!

Now, how exactly would you go about this? The first thing you would need is a list of celebrities. Since the “6 degrees of Kevin Bacon” game is usually done with movies, I figured it would be best to stick to movie actors. Also, I figured that I should choose successful actors with long careers, so the ones I choose could be used for as long as possible. So, I started with the Forbes Celebrity 100 list, in order of “Power Rank”. Next, I took out all the directors, producers, sports stars, authors and other people who didn't act in movies, and whittled my list down to the following people (in alphabetical order):

Jennifer Aniston
Tom Cruise
Johnny Depp
Mel Gibson
Nicole Kidman
Madonna
Julia Roberts
Will Smith
Denzel Washington
Oprah Winfrey

This list has the advantage of containing people who have had long careers in the movies, and won't be soon forgotten (hopefully).

Now, how are we going to remember all the links required? Would linking everyone on a list of 10 with each of the other 9 people require remembering 90 different lists? Not quite. Because a list from actor A to actor B is really the same as the list from actor B to actor A, only backwards. So there's really only 45 lists to remember, not 90. For example, the path from Jennifer Aniston to Tom Cruise is just the reverse of the list from Tom Cruise to Jennifer Aniston.

So, what I did was open up a spreadsheet program, a put the above list of actors along the top row, as well as down the leftmost column, making sure to do so in alphabetical order. Where each pair of different names meet will be the list of connecting movies and actors.

Now we come to one of the more important questions - How do we find all the links we need? Isn't that going to take a lot of time to find all 45 links? Without any help, it would. Thankfully, the Oracle of Bacon at Virginia comes to the rescue! Using this site's Star Links search, you can get a list of all 45 links together in about 10 minutes!

As I researched the links, I added them to the spreadsheet, until all the links were done. I always made the links from the person whose last name came first alphabetically, to the other person (I'll explain why shortly). So, I would put the link as going from Denzel Washington to Oprah Winfrey, but not the other way around.

Next, I use the basic linking technique to link the lists together. As visual images are needed, and movies are highly visual, these links are often quickly retained. When I'm not familiar with a linked actor or movie, I can either look them up in the Internet Movie Database (IMDb) to strengthen the links and/or use the substitute word method to help remember those links better.

Fortunately, all the actors on the list I created only have, at most, two intermediate movies and one intermediate actor to link them. The intermediate links always go movie-actor-movie. The link between Jennifer Aniston and Tom Cruise would read “Bruce Almighty-Morgan Freeman-War of the Worlds”, meaning that Jennifer Aniston was in Bruce Almighty with Morgan Freeman, who was in War of the Worlds with Tom Cruise.

Memorizing each link is somewhat akin to the Memory Chart concept. Since each person on the list, except Washington and Winfrey (who I think of as “Wash” and “Win” for the following purpose), have last names beginning with different letters, I think of words that can be created with those letters, and use those as links. Here are a few examples:

Jennifer Aniston and Tom Cruise=“AC”=“ACe”
“ACe”=“Bruce Almighty”+“Morgan Freeman”+“War of the Worlds”

Johnny Depp and Denzel Washington=“DWASH”=“Dirty WASH”
“Dirty WASH”=“Donnie Brasco”+“Zeljko Ivanek”+“The Manchurian Candidate”

(Fortunately, the Oracle of Bacon includes links to the IMDb, so you can learn more about the intermediate actors, if needed.)

Once you do this for 45 links, you're all set! With a flash card program that uses spaced repetition, such as SuperMemo, Genius or Studycard Studio, (all of which I've discussed before here and here) you can learn these quicker than even you may have thought!

Also, as time passes, you can add more and more actors to the list if you want. Who knows? Instead of having people draw the names of movie actors, you could get to the point where they simply name any well-known movie actors, and you can give the links!

For almost as long as I've had the Astonishment Site, Doug Canning has graciously allow me to teach his Mental Shopper in the memory section of the site.

Earlier this week, I moved it into the Mental “Feat”-ures section of the Mental Gym section. In addition, I've added a Javascript Quiz for Mental Shopper, so that you can practice it.

Just to get you curious, here's the description of the routine from the site: You hand the spectator 5 cards with 6 grocery item and their 3-digit prices on each one. The spectator calls out one item from each card, but not the price. Thanks to your powerful mind, you are able to not only recall the prices of the items, but add them up quickly in your head, as fast as a calculator!

Grey Matters has just received a glowing review in the “Head Trip” entry over at Dale A. Hildebrandt's blog!

It's also mentioned over at Dale's newest blog, called “The Devil Still Deals”, which is so new, the only entry in it simply reads, “Welcome to the new blog.”. If you're having trouble finding me, I'm right between Harry Lorayne and Anton LaVey.

You know, somehow I thought I would go through my entire life without using the phrase, “I'm right between Harry Lorayne and Anton LaVey.”

Here is a brief look around the web in the world of memory and math:

* Word is starting to spread about my Train Your Brain and Entertain software. Not only have I been getting hits from Apple's site, as I mentioned in this entry, but due to this mention in MacNN and LobowolfXXX's review at the Magic Cafe, the number of hits on the Grey Matters site has increased dramatically!

* Speaking of software, there are two new releases out that readers of this blog may enjoy. First, there is Brain Tease, which helps improve your short-term memory, concentration and focus, by using two simple exercises. The other program is Quiz Press, which lets you create multiple types of quizzes (multiple choice, fill-in-the-blanks, true/false and more), and lets you output them via your printer, PDF files and even a self-scoring Flash-based version for use on the web! Both programs are available for Mac OS X and Windows.

* Scientists are being baffled by a woman who can't forget. Instead of being autistic, or otherwise having trouble functioning in everyday life, she is as normal as you or I, except for her extraordinary memory. Read the full story for yourself!

* There's one week left in the "Shed Your Winter Layers Spring Sale" over at the Grey Matters Store! Until April 13th, you can save US$10 on any purchase over US$50 by entering the code SPRING10 during checkout. This is an excellent chance to get Train Your Brain and Entertain, along with your choice of a wide variety of apparel, including the new women's and men's shirts that were just released today. The new shirts feature the 400-digit "Pi Chart" on the back, and the phrase, "You know you've memorized too many digit of Pi when you not only have no life, but you can prove it mathematically!" on the front.

Harry Lorayne's newest book is called, "How to perform feats of Mathematical Wizardry". I've finally managed to get my hands on a copy, so here's the review I promised in my 100th post. First, the basics of the book. It comes as a 202-page, soft-bound book measuring 7.25 by 9.5 inches. Harry Lorayne not only wrote the book, but published it, as well.

Now, what about the contents? The contents are divided into 7 chapters, each with a different theme. Believe it or not, the very first effect the book is the ol' 1089 trick. Wait, come back! This effect is not so much written for its own sake, but as a launching pad for a discussion of the 9 principle, which forms the basis of the majority of the first chapter. If you've ever used the 9 principle in an effect before, but never been quite sure about why exactly it works, the effects and the discussion of them to be of great value. You quickly work up to feats such as adding six 5-digit numbers faster than a calculator, Pascal's triangle (discussed in detail), the classic Fibonacci addition feat (I'm not quite sure why this is in the "9 principle" chapter), and the "Missing Digit" feat. I've always loved this feat, in which someone multiplies two 3-digit numbers together, reads you every digit in the answer except for one of them, and you can name the missing digit (This can be done as a mind-reading feat, a memory feat or a lightning calculation feat)! There's a concept in here that I first learned from Harry's magazine Apocalypse, which is very subtle and clever. I'm almost sad to see it republished.

The second chapter deals with large series and groups of numbers. Here you start by learning how to add consecutive numbers, and then you learn how to take this basic principle into numerous directions . . . literally! There's even an excellent presentational touch for the Fibonacci addition trick that I'd never seen before. This chapter also includes multiplication feats, "Nim" and other object-moving games, and even a brief discussion of those hoary old algebra-based effects. These are the ones that usually begin something like, "Think of any number, add 5 to it, now multiply that by 50..." As is pointed out in the book, anyone with any math sense in your audience will usually see right through these. Even the author mentions that these tricks are included more for the sake of completeness.

Chapter 3 deals with numbers that, due to their special arrangement, give them unique properties that are well suited for mathematical feats. The first half of this chapter concerns feats using the arrangement of numbers on a calendar, including Mel Stover's "Irresistible Force" (which is also discussed in detail on Doug Dyment's website). The latter half of the chapter deals with specific numbers, such as 3,367 and 142,857, which have their own unique features.

Chapter 4 starts with a classic card effect and a classic coin effect (known as "Debit and Credit"), and then quickly moves onto magic squares! If you're thinking that I've examined this chapter more than any of the previous ones, you're right. Basic approaches to 3x3 and 4x4 magic squares are discussed, after which comes the largest single article in the entire book. Harry Lorayne wrote an excellent article on magic squares in the April 2005 issue of Genii, which I reviewed shortly after starting this blog. If you wished you hadn't missed this article, you'll be glad to know that you can find it in full in Mathematical Wizardry. Harry concludes this chapter with the interesting "To-And-Fro Magic Square" (which I'll let you discover for yourself).

Moving on to the fifth chapter, this one deals with rapid division and addition feats. There two major gems in this chapter are the "Additional Adding" routine, in which someone creates a random 6-digit number, and you instantly create a list of four 5-digit numbers that total that number, and the reprint of Alan Jackson's "Diabolical Divisors" from Apocalypse. In the Jackson routine, there are six phases. In each phase, your audience is asked to create random repeating numbers, and you're able to give larger and larger divisors for the numbers each time. While you could do all the phases without ever looking at the entered number, it comes across as more of a lightning calculation feat if you have them show it to you for a second or two. There are some great presentational hints for this effect here, that weren't in the original Apocalypse write-up. This routine is hidden at the end of the plainly-titled "Another 'Combination'" routine, so I haves this will help it remain hidden, and I can keep using it to amaze people.

The sixth chapter is dedicated to classic routines of varying types. The first routine is the recall of the day of the week for any date in the current year, which I've talked about numerous times on this blog. Even if you just do the current year, as opposed to the version in which you can do any year, this is very impressive. Right after that, there's Hummer's classic 3-object divination. Here, you're taught the classic version, as well as a version in which you don't even have to look at the items to determine the mentally chosen object. If you're not familiar with Hummer's 3-object divination, you need to get this book just for this routine. Ever since I first discovered this effect in the March 1990 issue of Genii, I've had it in my arsenal.

Many books of effects have at least one "hodge podge" chapter, a chapter in which everything that didn't fit else into the other sections is presented. This chapter includes some feats that could also be used as memory feats. There's the memory magic square, originally from Lorayne's Reputation Makers. Also along this line is "TAELBPAH", in which you learn to say and/or write the alphabet backwards and forwards, at the same time. This is not only an impressive feat on its own, but would also work well as a closer for those who do "Learning the Almost Impossible", the routine in which you teach the audience to say the alphabet backwards from the first volume of Mentalism Incorporated. Among the puzzles and odds and ends in this chapter, you also learn how to square any two digit number mentally.

One of the criticisms of this book is that so much of the material has seen print before. This is true. For example, you can learn a two-digit squaring method on the Mathpath site. In Harry's favor, he often presents new touches for these older feats that really helps improve their presentation. Also, there are enough routines here that I haven't run across that often, that do make this book valuable. The quality of the material as a whole is also much higher than the average collection of mathematical magic.

Overall, I would recommend this book to those who are looking for a great collection of mathematical routines in a single book.

One of the things regular visitors to this site want to see is the latest in forgetting techniques, and the occasional super-forgetting demonstration. If you are just such a visitor, you'll definitely enjoy today's entry.

Starting with the basics of forgetting, there is a very thorough article over at MentatWiki called HowToForget that gives some great tips. These should be studied closely, as we all know, our schools focus far too little on techniques for forgetting.

If this seems like too much work, there are some wonderful pseudo-forgetting demonstrations out there. In the book Self-Working Number Magic, there's a great, yet simple stage routine, called Memorease. In this effect, one of three people is given a magic amulet, which causes the remaining two to suddenly gain the ability to forget a list of letters they were just shown! The person with the amulet, of course, is still able to remember the list of letters perfectly, as usual.

This effect also appears in Chronicles, along with a similar version called Memory, which uses a list of words, instead of letters.

If close-up is more your style, you may want to check out Eugene Burger's Observo. No matter how many times you show two spectators the same packet of cards, neither of them can agree on any of the details, thus proving that you, as the performer, have magically given them the gift of super-forgetting! Eugene Burger himself can be seen talking about the routine in detail in a free video, available in both QuickTime and Windows Media formats.

Harry Anderson has his own version of this type of routine. It's called Shadow Card, and uses a single card, on which none of four people can agree. When the card is finally shown, none of the four is correct!

Finally, I should mention the most etherial of the super-forgetting routines. Not surprisingly, it comes from Wonder Wizards. The routine is from Luke Jermay's 7 Deceptions, and is described as follows: “A spectator looks at a playing card. You cause the spectator to forget this card, and they cannot remember it. Included in this full explanation is how to cause people to forget their name temporarily and much more. Yes, you CAN do it!” Unfortunately, I haven't had a chance to review the book personally, so I can't speak as to how this routine plays, or give any details about it.

Oh, one last thing before I finish up this post. Did I remember to wish you all a happy April Fools Day?