3.14......the 1st 3 numbers of pi......a triangle, a circle and a square..........the 3 most basic shapes.

Pi Day and Albert Einstein Birthday: Why 3.14 Is Called Pi | Time

time.com › History › Education

Mar 14, 2017 - The significance of the number 3.14—the inspiration for Pi Day on March 14— was known in Ancient Greece, but it wasn't called "pi" till later.