I came back from my vacation, only to discover some sad news. Kim Peek, the savant who inspired the hit movie Rain Man, has died of a heart attack on December 19, 2009.

Kim Peek's savant condition allows him to remember everything he has ever read. In the following clip, Kim shows off this powerful ability at the first (and unfortunately only) meeting of the Athanasius Kircher Society.

I'll be on vacation through the end of the year. Don't worry, Grey Matters will return with new posts on January 3rd, 2010!

I did arrange for some help with the Timed Quizzes post, so updates on that post will continue as normal.

In the meantime, look around the site via the menu at the top, or explore the blog entries, which go back to March of 2005, via the menu on the side. You may find something on the site you never knew about!

Two years ago, just before Christmas, I examined the mathematics of The 12 Days of Christmas.

This year, singingbanana, whom you may remember from the 15 Puzzle Challenges post earlier this month, gives us a great new way to visualize triangular numbers in a very Christmasy fashion:

Greetings, memorized deck fans! Today, we have a new treat for you.

Over at Furniture´s Card Magic Corner, Furniture has posted a new memorized deck tool called the Tamariz Memorized Stack (Mnemonica) Trainer.

It's a spreadsheet file with 3 tabs, and can be viewed online in Google Docs. The 1st tab simply holds the deck order, the 2nd tab challenges you to recall a card by its position and vice-versa. The 3rd tab is a bonus, and will help quiz you on how to cut to a particular card, in order to deliver it to a given position.

Besides using it online, you can also download it from Google Docs, and use it offline in programs like Excel or Numbers.

For those of you who use the Aronson stack, MemDeck329 has already prepared a new version for you, which is available as a zip file here. If you use a different stack, the spreadsheet is easily altered to fit your stack in the 1st tab.

If you find this useful, you'll probably also enjoy these other free online memorized deck tools.

I recently sprained my arm, so I'm going to keep today's column short to minimize typing.

One of Grey Matter's favorite performers, Arthur Benjamin, returns for this post in a short, yet interesting, talk about to improve math education.