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Savor a virtual piece of pi

Exploratorium / Linden Labs
A Second Life resident visits Pi-Henge, one of the Exploratorium's Pi Day exhibits.

San Francisco's Exploratorium makes an irrationally big deal out of pi: For 20 years, geeks have gathered at the science museum to troop in circular processions, solve pesky puzzles, string beads and consume mass quantities of pie - all building to a peak on 3/14 at 1:59 p.m., when the time lines up to form the first six digits of the mysterious and marvelous number.

This year marks a nice round number for Pi Day, an observance honoring one of the least-round numbers in mathematics. You don't even have to be at the Exploratorium to savor the 20th-anniversary celebration. Online resources, ranging from Web sites to the virtual world known as Second Life, are serving up a substantial slice of the Pi Day experience.

Physicist Larry Shaw told me he had no idea Pi Day would be such a big deal when he came up with the idea back in 1988. The first observance was something of a lark, a spin-off (so to speak) from Shaw's musings on the rotational relationship between one dimension and another.

The idea behind pi is simplicity itself: the ratio of a circle's circumference to its width. But putting a precise value on the number seems to be beyond the power of the world's most sophisticated computers. Pi's value has been calculated to a length of more than a trillion digits, with no end in sight.

It's that combination of pi's simplicity and irrationality that continues to capture Shaw's imagination, even after 20 years. "It is not ultimately determinable - that's basically the mystery behind it," he said today.

It's also a good excuse for a party - and the party is a good excuse for getting future generations hooked on math, just as Archimedes was hooked more than 2,000 years ago.

"Part of science teaching is engendering interest in the kids," Shaw said. "Anything that has some fun to it, the kids will just jump into it. And that's part of the reason for doing it. ... It's an excuse for a lot of things that are out of the ordinary in the classroom."

For the first observance, Shaw and his colleagues installed a small brass plate, engraved with the first 100 digits of pi, at the very center of a circular classroom at the museum. They walked around their shrine to pi. "People go around things to show respect to them in many cultures and religions," Shaw explained. Then they did something which is not a feature of all that many religions: They had pie.

Shaw, who has since retired from his post as a staff physicist, has been gearing up for Friday's observance for some time: The celebrants will walk around the shrine a little more than three times, add beads representing the numbers zero through nine to a ritual string of more than 1,600 digits - and, of course, gobble down pizza pie as well as fruit pie.

So go ahead and check out the offerings at the Exploratorium's Pi Day site, at PiDay.org and WikiHow. If you're a Second Life resident, take in the Leaning Tower of Pie-sa, Pi-Henge and other educational exhibits built by the Exploratorium. You can even sing a song to pi. (I like this archived video from Rocketboom, but Shaw goes with a synthesized voice singing to the tune of "Pomp and Circumstance.")

Oh, and don't forget to sing "Happy Birthday" to Albert Einstein while you're at it. Friday marks the 129th anniversary of the late physicist's birth - making the day a doubly fitting occasion to raise a glass (or a forkful of pie) in his honor.