Pi, the mathematical constant that is the ratio between the circumference and the diameter of a circle, leads to strange areas. Often abbreviated as 3.14159, pi has no apparent end; the digits after the decimal continue on as far as your determination (or endurance) allows you to compute. A trillion digits of pi have been reckoned by high-power computers, and there's no simple pattern to the numbers that crop up — and yet there are intriguing combinations of digits that hint at a pattern, maybe. The mystery of pi's infinite state tantalizes mathematicians who pursue it. Ludolph van Ceulen computed the first 35 digits of pi and had the achievement immortalized on his tombstone. Chao Lu memorized 67,890 letters — and recited them without error over a 24-hour period. And then there's the

March 14-17, 2008

*Cadaeic Cadenza*, a short story written by Mike Keith; the number of letters in each word of the story correspond to the digits in pi exactly, and the words themselves reference the works of Poe, the*Rubaiyat*and the lyrics of Yes. The Saint Louis Science Center (5050 Oakland Avenue; 314-289-4400 or www.slsc.org) hails the irrationality with the**Celebration of Pi**Friday through Monday (March 14 through 17). Pi trivia, a pi-themed scavenger hunt and real-world applications of pi's usefulness (size comparison of round pizzas, of course) serve as your entry into the maddening world of a number without end. Talk pi, compute pi, play with pi — just don't expect to fully comprehend it. Admission is free every day.March 14-17, 2008