Just like we have YouTube for videos and Slideshare for slideshows, we now have Quizlet for flashcards!

Quizlet is a free online application that lets you create, learn and share flashcards on any subject. It will even create tests of a style and size you specify. If you're familiar with any of the flashcard programs I reviewed back in October and November 2005, then you'll appreciate the ease-of-use and cross-platform nature of Quizlet.

To get a better idea of what I'm talking about, go over to Quizlet and click on the images on the front page, using your arrow keys to go through the tour.

As this seems to be a great way to aid in just about any item that requires memorization, I can see this becoming a very interesting and useful tool for Grey Matters in the future.

The graphic that opened the previous entry is great for computers, but what if you want to approximate Pi in the real world?

Just throw frozen hot dogs! Sure, it may seem silly, but this random act approximates Pi quite well. If you're not up to throwing actual hot dogs, two Java simulations, one here and one here, will help save your dinner. If you're curious as to how needles and hot dogs seem to inherently known what Pi is, Cut The Knot offers a great explanation of what is known as Buffon's Needle Problem.

Instead of visualizing Pi, it can also be audiolized. One of the simplest ways is to assign a note to each digit as in this Pi MP3 or this Pi WAV. Approached this way, you can find some interesting musical sequences in Pi. Of course, you can also use Pi as the subject for a song, which has been done in genres ranging from classic rock to rap.

There are as many ways to have fun with Pi are there are digits in it. I can't list them all, of course, but sites like Teach Pi and Pi Nation provide great starting points for further Pi fun.

Pi is the ratio of a circle's circumference to its diameter. Huh?!? When clothed in mathematical mumbo-jumbo, the concept can sound confusing. John Reid's animated definition of Pi (above) says exactly the same thing, but the animation makes it so much clearer.

The graphic itself was the January 20, 2007 Wikipedia featured animation of the day, but is usually found on the main Wikipedia article on Pi.

The animation also demonstrates Pi's unintuitive nature. The distance across the wheel is relatively easy to approximate at a glance, but it still seems incredible that the distance around it can be over 3 times the diameter! If you want a better idea of how deceptive this can be to people, you can even use this concept to win bar bets! Yes, Pi is actually useful in the real world.

The real world is one thing, but it has also been the subject of much play. For example, you can search for your birthday in Pi. Back in 1995, Mike Keith rewrote Edgar Allen Poe's classic poem The Raven as a Pi mnemonic (Note: My original link to the poem is no longer available)! He called it Poe, E.: Near A Raven. He later incorporated into a second, longer work which he titled Cadaeic Cadenza. I highly recommend taking the time to read the latter in full, even if you have to break it up into several sessions. His handling of the Feynman point is particularly ingenious.

In short, take Pi seriously when needed, have fun with it otherwise.

First, thank you to everyone who commented and e-mailed me concerning the recent slideshow upgrade. Originally, I thought the slideshow would be a better teaching format. After listening to several e-mails, and realizing that different people learn in different ways, I've improved the Grey Matters Mental Gym.

If you look over at the Mental “Feat”-ures page you'll note that both the Serial Number Feat and the Root Extractions section now feature text and slideshow options. Also, as you go through the pages, you can still switch between text and slideshow at any given time. Take a look at the Cube Root slideshow, for example. If you would rather read the original text, simply click on the text version link above it, and you'll instantly get the Cube Root text page, instead.

Turning to the Presentation section, I've added some external links for great presentation resources. There's Richard Tenace's Stage Stuff column from Online Visions. Another great set of links is to Dramatica.com and the Daily Dramatica Blog. If you're not already familiar with it, see my Dramatica review.

The one other site I included, the Creating Passionate Users Blog may seem like a strange choice, as its focus is on improving web design for your users. However, this site frequently talks about the principles of making your web users happy, and these are often applicable to audiences watching a performance. Check out the ...but is it memorable? post, and ask yourself where your performance falls on that graph.

As time goes on, I will of course be adding more and more to each of these sections. For now, though, there's plenty to explore in these new additions!

A “lightning calculator”, for those not familiar with the term, is simply someone who can perform seemingly complex math in their head very quickly. They're also often called “Human Calculators”. To get a better idea of what a lightning calculator is, you can watch people such as Badri Narayanan, Scott Flansburg, Ruediger Gamm, Daniel Tammet (The full documentary is also available), Arthur Benjamin and Mike Byster.

While you can see current masters of the art on video, you can also learn about lightning calculators of the past, as well. One such past master was Alexander Aitken (pictured above), who is regarded among the best of them.

Part of the original lure of this type of act, as a form of entertainment, spoke to human potential. It demonstrated that the human brain was capable of amazingly complex tasks, and even suggested that the brain had limitless potential. Much like super memory acts, they changed their audience's ideas about what was possible (at least when presented well).

Lightning calculators usually fell into one of two camps. First, there were the savants, many of whom had a natural ability with numbers.

The other group were people who had learned and practiced feats of mental math. If you would like to try your hand at such feats, there are numerous resources available. Among my favorites are the Mental Gym, Arthur Benjamin's videos, BEATCALC, MathPath, the Lightning Calcuator book and Mike Byster's Math Shortcuts. With this kind of help, you may be able to perform as a lightning calculator yourself.

As an entertainment, it used to be a vastly more popular form of entertainment than it is now. Over at The Volokh Conspiracy, they theorize the pocket calculator was the largely responsible. However, the current issue of Plus Magazine (issue 41, at this writing) delves deeper in the issue of the death of the lightning calculator.

I would like to suggest that writing about the death of lightning calculators is premature. First, with the right presentation, a human calculator act could be more impressive today than ever. Performed as a man vs. machine challenge, especially with today's fast computers, this could be a big hit.

Even though, as the Plus article suggests, there is a politically correct argument against savants using their skills in this way, this isn't always the case. Not all savants are helpless, disabled people. Kim Peek tours schools, and inspired the movie Rain Man, while Daniel Tammet runs his own company. If a savant were to decide to do such an act out of his or her own free will, I don't think it should be considered exploitation.

I hope you've enjoyed this look into the little-explored world of lightning calculators.

Many magic books that come out these days are an attempt to show the author's swiftness with their hands. Bits and Bytes by Dale Hildebrandt, however, showcases a deft mind and a great ability at lateral thinking!

To get an idea of Dale's mind, beyond just the Lybrary.com Author Info page, check out his main site, mirrorname.com, as well as his various blogs, Dale's Den, The Devil Still Deals and Ultimate Nerd.

Bits and Bytes itself is an 84-page e-book filled with wonderfully whimsical routines. Much of the work originated as variations of the work of magician Liam Montier. The book kicks the mood right off with D. D. Home, in which you can prove the spirit of a Victorian medium is invading your friend's Windows XP computer. This is a rarity in magic, as you don't need to ever touch the computer to achieve the effect.

While there are a good number of effects involving high-tech gadgetry, including cell phones and computers, don't let the name of the e-book fool you into thinking that this is the only type of magic that is included.

Among my favorites in the book are the Tossed Out Wallet Ploy (a combination of the Tossed Out Deck and Bank Night, with 4 bills of different denominations), The Perfume Test (a spectator finds the 1 bottle filled with perfume among 3 others containing water), The Card and the Crane (a card prediction using a crane game) and the Fortune Telling Card Fish (finally, a deceptive effect involving the old Fortune Telling Fish!).

Special attention should be paid to the Forcing Board and Other Ploys section towards the back. It involves a board that has the numbers 1 through 53 on one side, and all the playing cards on the other. Basically, someone thinks of a card and a number, and you are able to reveal them. Several wonderful subtleties go together to make the use of this board a seeming miracle! This basic idea is also the introduction to a discussion between Liam and Dale discussing various directions in which to take the basic idea. Even if you never use the effect, the back-and-forth nature of the discussion is an excellent lesson in how new ideas can be inspired.

There are also some wonderful gags and bits throughout the book, as well. As with anything else, these will work great if they suit your performing persona.

If outside of the box plots and thinking appeals to you, head over to Lybrary.com and plunk down the money for Bits and Bytes!

Here's some quick and fun items I thought I'd share from my journeys around the web:

* You've probably played or seen chess programs, but Thinking Machine 4 is a different animal. Yes, you can play chess with it, but it's structured to allow you to see the thinking process as it's taking place, as shown in the gallery. If you enjoy the show Numb3rs, like I do, it's akin to watching “Charlievision”, which are the segments where the audience gets to see Charlie Eppes' (David Krumholtz) inspirations for his mathematical solutions.

* Speaking of TV, if you enjoy the show Mythbusters, you can now check out the Mythbusters Results website! As you might guess by the name, you can check out the outcome of any of their experiments. Between this site, Snopes and The Straight Dope, you should be able to find out the truth about almost any well-known myth.

* David Brown, in an online article called Calendar savants & date calculating, teaches an interesting approach to the classic day for any date feat that is far simpler than any approach I've previously seen. The explanation is thorough and easily understood.

* Cool Science Facts is a blog that truly lives up to its name. The greatest thing about this blog is how it helps make you smarter bit by bit, as you read the entries. My favorite, of course, is the Pi entry.

Computer Science. This is one of the worst possible names you could give it. Imagine if, instead of calling it astronomy, we called it Telescope Science. The name focuses too much on the tool, and not at all on the true study at hand.

Computer science is the study of of the theoretical foundations of information and computation and their implementation and application in computer systems. In this definition, note that the computer system comes last, and that it is truly about the implementation and application of the information itself.

But, surely you would need computers to teach computer science, wouldn't you? The people at Computer Science Unplugged don't think so! To get an idea of how this is done, check out one of their clips I posted over in Grey Matters Videos, or their other video clips, for that matter. They even have free files explaining these concepts in full detail. They do have a complete course available, as well.

Much like this site's focus on memory and mental math techniques in a fun and entertaining manner, computer science can be (and even should be) fun! There is even a magazine called Computer Science For Fun, or cs4fn for short. You can download the all the issues of cs4fn here. Among the articles of particular interest to Grey Matters readers in the first issue are the mathemagic section and the article that may best you at tic-tac-toe!

The fun aspect of computer science isn't a new phenomenon, either. Check out the Best of Creative Computing, vols. 1, 2 and 3. Creative Computing was a magazine from the 1970s, a computing era before personal computers that gave birth to some of the largest computer companies still in existence. Above and beyond the articles themselves, you really get a feel for what people like Steve Jobs and Bill Gates were growing up with in the 70's computer scene. The predictions about where computer science will go in the 1980's and beyond are a fascinating read in retrospect, as well.

Even if you're not normally interested in computer science, I recommend at least taking a casual glance through each of these references. You may even wind up with a surprising new interest, or maybe just learn one new thing you didn't know before.

Happy New Year! The changes I hinted at in an earlier post are now ready! With the new year and the new Blogger both ready, it seemed time for a change and plenty of new features.

What are the new features, you ask? Features that make Grey Matters easier to use than ever! I'll work from the top of the blog downward.

First up is the peek-a-boo Blogger navigation bar. It's out of the way until you mouseover the very top of the page, at which point it functions the same as it always has.

Just below that is the Grey Matters navigation bar, which will take you to all the sections of Grey Matters with just one click. I've made this more detailed than the previous bar.

In the blog entries themselves, you can now click the title to bring up the individual post and its comments. This can also be done with the time stamp at the end of the article.

One of the cooler newer features, the labels, has been updated and improved. When you click any label at the end of a post, it will bring up all the title of all other posts that share that same label. Clicking on the symbol next to any title [+/-] on that list will show the entry itself, and clicking on the title in that list will show the full entry, including the comments.

Also, at the bottom of the blog section, and even searches and individual entries, you'll find links to older and newer posts (as well as the main page), allowing to browse through the blog chronologically.

Over in the rightmost column, there are two new features that will also greatly ease your navigation of the site. The first is the Label Cloud. This is a list of all the labels I use, with the larger labels representing the more frequently-used labels. The other new feature in that column is the Blog Archive section, which is organized by year and month, so you can quickly and easily bring up posts from any time.

Between the subject and chronological organization that these new features allow, as well as the older/newer post browsing and the Search and Site Feed sections, you should now find that surfing this site is simpler than ever!