# It’s Pi Day! Here are 3.14 facts about pi

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You know the old saying: it's Pi Day, Pi Day, gotta get down on Pi Day. And what better way to celebrate the date that embodies everyone's favorite mathematical constant than with precisely 3.14 facts about pi.

#### 1 — A Japanese memory master Claims he can recite pi to 111,700 digits

Memorizing pi is an undeniably nerdy pursuit, but some people have taken the challenge to extreme lengths. Japanese memory master Akira Haraguchi has recited 100,000 digits of pi in public (it took more than 16 hours), and told The Guardian that his personal record goes to 111,700 digits. Haraguchi's technique relies on assigning symbols to numbers, turning pi's random sequence of digits into stories — mostly, he says, about animals and plants.

"To me, reciting pi’s digits has the same meaning as chanting the Buddhist mantra and meditating," Haraguchi told The Guardian in 2015. "According to Zen Buddhism teachings, everything that exists in this world — the mountains, the rivers and all the living creatures — carries the spirit of the Buddha. I’ve interpreted this to mean that everything that circles around carries the spirit of the Buddha. I think pi is the ultimate example of that."

A visual representation of pi. (Image credit: Creative Commons)

#### 2 — We know way more digits of pi than we need to

Pi may have transcended mere numberhood to become a cultural symbol, but it still has practical uses. As these examples show, engineers and scientists need pi for all sorts of tasks, including calculating flight paths (as the planes are traveling on an arc of a circle) and audio processing (as pi is used to calculate sine waves).

But calculations like these only need between five to 15 digits to be accurate, and we currently know pi to quadrillions of digits. Finding digits of pi may be a favorite pastime for researchers with idle supercomputers, but this is mostly just showing off. To get an idea of how unnecessary these digits are for practical calculations, consider the fact that you only need 39 digits of pi to calculate the circumference of the universe to the accuracy of the width of a hydrogen atom.

#### 3 — Pi has its own literary form: pilish

"Yes, I have a robot disguised as Nikola Tesla." This is my (sadly inaccurate) attempt at writing in pilish: a literary form in which the number of letters in each successive word match the digits of pi. The restrictive nature of pilish means it's not particularly good for longer works, but the acknowledged master of pilish — mathematician Michael Keith — has written a novella that follows pi's digits for 10,000 decimals.

Scientists have searched published works for examples of accidental pilish, but there seem to be few examples of any note. Happily, though, one of the earliest (intentional) examples of pilish is one of the most apposite. It's thought to have been composed by English physicist James Hopwood Jeans and runs as follows: "How I need a drink, alcoholic in nature, after the heavy lectures involving quantum mechanics!"