Maths

"You have to spend some energy and effort to
see the beauty of Math"
Maryam Mirzahani, 1977-2017

Pi Day is the perfect date to publish this piece of mail sent by Phillip (the USA). 

The shadowy stamp is dedicated to Women Cryptologists of World War II. You can read more about the stamp here and here. I love especially the First Day of Issue pictorial postmark. It includes a a coded message that contains the date and location of stamps issuance: October 18, 2022, Annapolis Junction, MD20701.

(Approximation of) Pi Day Mail

Envelope sent by FinnBadger (the USA), with a special pictorial postmark that celebrates Pi Day. And, of course, this had to be accompanied by a round stamp!

Did you know that Pi Day was a thing? And it also exists the Pi Approximation Day, which happens to be today, since the fraction ²²⁄₇ is a common approximation of π.

Have you ever sent/received π-related mail? I have just read on the Wikipedia:

Massachusetts Institute of Technology has often mailed its application decision letters to prospective students for delivery on Pi Day.