Hi friend @brian.rrr how are you ?. In my case it's the first time I've heard about the day Pi and when I read the publication I liked it a lot since in my case I hardly read the day of the day I already knew what you were referring to, since in high school and in the university I saw a lot Mathematical constants in the subjects of mathematics, physics and statistics, although I was not very good in those subjects if I solved the exercises studying a lot. As you mention it, the pi is used mostly with formulas to calculate the circle and diameter of a circle or a rectangular triangle. I congratulate your wife and you for this day, and surely that pizza pie was exquisite. Greetings to you and your beautiful family friend.