# There's a Hidden Connection Between Pi and Quantum Mechanics

Physicists have uncovered a hidden connection between a famous 350-year-old mathematical formula for pi, everyone’s favorite irrational number, and quantum mechanics. At least one mathematician has pronounced the discovery “a cunning piece of magic.”

# 16 Fun Projects for Your New Raspberry Pi

The new Raspberry Pi is smaller, cheaper and more energy efficient—not a bad way to update a best-selling device. Whether you've taken the plunge on one of the new units or you want to put the original model to good use, we've collected together some of the most fun Pi-based projects on the planet for you to have a…

# How to Calculate Pi with a Shotgun

We all know pi, at least the first three digits of it. If for some reason you forgot them though, there's good news. All you need to get that knowledge back is some aluminum foil, ingenuity, and a shotgun.

# Visualization reveals how the number Pi looks (spoiler: Pretty!)

Cristian Ilies Vasile has created the coolest visualization of Pi I've seen. First he divided a circle in 10 segments, from 0 to 9. Then he traced a path going from the third segment to the first segment. From 1, the path jumps to 4, then back to 1, then 5 and so on. After a while, π appears in front of your eyes.…

# Why Pi is a stupid number and people are dumb to celebrate it

Recreational mathemusician Victoria Hart—aka Vi Hart—gives overwhelming (and fun!) evidence that clearly demonstrates that Pi is a stupidly common number and the fascination of people with this number is just dumb.

# Space-Pi!

Pi is for planets, and spacecraft, for orbital dynamics and craters. It's 3.14, and it's all about circles.

# When it comes to calculating pi, two wrongs might make a right

A great deal of time has been spent working out the facts about pi. At one point, the "facts" were wrong. And a mathematician caught the error by using something that, well, might also be wrong.

# You've Never Seen Pi Look So Interesting in So Many Ways

Martin Krzywinski is an artist. No, wait, he's a mathematician. Actually, scratch that: he's both, and he can make the number Pi look insanely beautiful.

# Why don't the Simpsons live in a base 8 world?

The latest episode of Numberphile delves into a particularly interesting reference to pi from the Simpsons episode "Marge in Chains," while raising the very valid question as to why the Simpsons – who have eight fingers apiece – don't live in a base eight world.

# Experience the number π as you never have before

Unless, that is, you're a synesthete. (You're about to experience a number through music!)

# Will you be having a pi party?

Do you feel like having a once-every-thousand-year party? You only have a couple of years to set it up. Some of us will be planning 2015 Pi Parties — in some cases because we like math, and in other cases because we want an excuse to eat pie for breakfast. Let us know if you're going to be involved.

# 7 Numbers That Are Just as Cool as Pi

We may be celebrating Pi Day here at io9, but we would be irrational to deny that there’s more to mathematical interestingness than simply dividing an object’s circumference by its diameter. Here are seven numbers we love as much as pi.

# Pi Was Almost 3.2

When an amateur mathematician from Indiana managed to solve one of mathematics' great problems—squaring the circle—he decided to copyright his proof, but allow his home state to use it for free. Sadly, things didn't quite go to plan.

# How Many Digits of Pi Do You Really Need?

Pi is famously calculated to trillions of digits—but how many of them do we really, really need? This video demonstrates that, actually, just 39 will do.

# Wash Your Scotch Down With a Heaping Helping of Pi

How many numbers of Pi can you rattle off? Probably not many. Probably even fewer if you're drunk. But you can at least cheat with these glasses from TheUncommonGreen that are printed with hundreds and hundreds of digits from the mathematical constant.

# Artist Skywrites the First Thousand Digits of Pi over San Francisco

Any eyes in San Francisco that weren't focused on Apple's announcements yesterday might have noticed something peculiar in the skies over the Bay area. As part of the ZERO1 Biennial—a months long festival celebrating the coming together of art and technology—an artist known only as Ishky used several planes to…

# The first 4,000,000 digits of Pi, visualized in a single image

Pi is what's known as an irrational number, which means that its decimal representation is both infinite and non-repeating.

# Who says you can't use maths in your daily life?

Pro-tip on pi-tips: this will come off as even more clever if you actually ordered pie. Or a pi pie.

# If You Read Pi Long Enough, You'll Find Hamlet

It's Pi Day! Which, okay, whatever, if you were really hardcore about celebrating you'd figure out what nanosecond corresponds to 3.14159 or whatever and pop the Moet then but you didn't and you won't so whatever, right? But! That doesn't mean we can't still have some fun with the nerdiest holiday in the land,…