Other than some kind of push to get people interested in math, I don't know we need a National Π Day, but we have it. And, at least, the day is well chosen: March 14 (or 3/14) for the 3.14 the Greek letter represents in math. Though it may just be something we learn in prealgebra, fascination over the symbol is dotted throughout pop culture. Why pi though?
In its simplest sense, pi is the ratio of a circle's circumference to its diameter. For most of us, it never meant anything more than plugging 3.14 into math problems, but to mathematicians the number is mind-boggling because its decimal points extend to infinity. Since there are, mercifully, few unknowns in math, the sign has become synonymous with mystery, crossing over from math and science to pop culture. To see how, keep reading.
- The Simpsons: A sign at the Springfield graveyard can't resist the pie pun, but cleverly adds its other meaning, saying "Come for the funeral, stay for the Π."
- Life of Pi: Yann Martel's main character in Life of Pi is not Pi, but Piscine; however, the character introduces himself at one point like this: "My name is Piscine Molitor Patel known to all as Pi Patel. For good measure I added ¼ = 3:14 and I then drew a large circle which I sliced in two with a diameter, to evoke that basic lesson of geometry."
- Twin Peaks: A show about mystery itself, it's no surprise creator David Lynch worked pi into the show — right down to solver-of-mysteries FBI Special Agent Dale Cooper being obsessed with eating pie.
Most references are subtle but pop up if you're looking for them. It's the secret code in Alfred Hitchcock's Torn Curtain, and the 1998 film Π and Kate Bush's "Pi" have been named after it.
Can you think of any I missed?