A gift from friends several years ago, it used to hang in my campus office. Interestingly, though there would be many, many possibilities, π does not figure in any of these expressions for the numbers 1–12! (E.g., cos(π/2) = 1 so 2 = π/arccos(1).) Nevertheless, it's appropriate for Pi Day because the clock is a circle. :-)
Retired economics professor (“dismal scientist”). Married 40+ years to the love of my life; we have two grown daughters, both married, two granddaughters and a...