Happy Pi Day! Every year on March 14, people around the world celebrate Pi, the mathematical constant that is the ratio of a circle's circumference to its diameter. That number, represented by the Greek letter "π," starts with 3.14159, with more digits stretching on infinitely.
On social media sites like Twitter, Facebook, and Instagram, users channeled their inner mathematicians and had some tongue-in-cheek fun with the date.
Unsurprisingly, a lot of users on photo-sharing app Instagram, decided to send out lots of images of tasty looking pies.
On Facebook, the Massachusetts Institute of Technology honored both Einstein and the numerical constant.
Even the Nobel Prize committee commemorated the day, with a Facebook message posted at the moment of peak Pi, precisely 1:59 p.m.