π (11. 420)

As our faithful chronicler reminds, today marks the annual celebration of the mathematical constant pi, expressed in US calendar conventions 3.14 (we also get the chance on the twenty-second of July, Pi Approximation Day, from the notional fraction known from the time of Archimedes—first observed in 1988 by physicist and curator of the the San Francisco Exploratorium Larry Shaw, and since designated by the US Congress and UNESCO as the International Day of Mathematics. Activities include learning about the irrational and transcendent number and its properties, memorising and reciting its digits, called piphilogy and relies on mnemonic techniques, such as composing so called piems—a portmanteau of the Greek symbol and poem in which the letter count of each word equals the corresponding digit: to the fourteenth decimal place, “How I want a drink, alcoholic of course, after the heavy chapters involving quantum mechanics,” and eating circular foods. The Massachusetts Institute of Technology also traditionally dispatched its college admissions decision letters to applicants on this day.