I can't believe that I don't have a photo of pie to enter here.
Here's a photo of a chocolate orange danish I ate with a knife in lieu.
Joking aside, Pi is basically the biggest discovery ever in the world of mathematics. Pi (represented by the greek symbol П) is an irrational number (it can't be expressed by a simple fraction eg 1/4 or 5/10) that represents the ratio of a circles circumference to its diameter. Because it's an irrational number, no one actually knows its exact figure - it has been calculated to millions of digits, but it (theoretically) will go on for an infinite number of digits. I remember when I was doing my GCSE Maths that 2Пr was a really important formula for measuring something to do with circles.
I also remember mucking about with the circumference of a circle and formulating a way to almost get the right answer by slicing the circle up into 360 triangles, measuring one of them, and multiplying by 360.
Again, can't quite believe that I don't have a picture of a pizza. Here's pate on a cracker instead.
It was a lot of effort to get the wrong answer.
Anyway, if you're a mathematician I hope you have a good П day! If you'd like to celebrate П day then apparently common ways to do this is by discussing the relevance of the number П, and eating or throwing pies.
Again, no picture of a pie! Here's a bacon sandwich.
