today (28/6) is Tau Day!

τ is one of the most important constants, and is defined as the ratio of a circle's circumference to its radius (approx 6.2832)

it occurs in many important math and physics formulas, such as Euler's identity which relates five of the fundamental constants:

e^(iτ)=1+0

which proves that what goes around comes around

τ is also culturally significant because the arbitrary number τ/2 is perceived to have magical properties