Pi and pie are inextricably linked—the homonyms both relate to circles (pi measures the ratio of a circle’s circumference to its diameter, pies are circular), and if you write down 3.14 and hold it up to a mirror, IT SPELLS PIE.
Clearly, then, Pi Day is a secret and dastardly plan created by mathematics to convince us to eat more delicious, delicious pie. And we happily fell for it. Grab your forks and your protractors, people. It’s time to eat.