Three months ago the world (or at least the geek world) celebrated Pi Day of the Century (3/14/15…). Today (6/28) is another math day: 2π-day, or Tau Day (2π = 6.28319…). Some say that Tau Day is really the day to celebrate, and that τ(=2π) should be the most prominent constant, not π. It all … Continue reading 2 Pi or Not 2 Pi?