The ratio of a circle's circumference to its diameter, an irrational and transcendental number approximately equal to 3.14159…, written with the Greek letter π.
In 1897, the Indiana House passed a bill that effectively made pi 3.2, 67–0. Its author, an amateur mathematician, thought he had squared the circle and offered free school rights. Purdue professor Clarence Waldo saw it in the Senate, explained the error, and the bill was tabled.