# Happy Half-Tau Day!

Hey, it’s National Pi Day again, and what would such a holiday be without the obligatory homonymic pun?   Here you go:

If you’ll permit to go one more level of visual punnery, let’s take the usual aural symmetry gag and augment it via a visually symmetric one as well:

Of course, me personally, I’m still rooting for the acceptance of $tau$, the value defined as twice $pi$.   If you don’t know about this, go read the Tau Manifesto and come back (I’ll wait).

In deference to this superior constant, I’ll note that the symbol $tau$ is chosen for several reasons:

1. It’s the first letter in the Greek word for turn, indicating it measures one full rotation of the circle, which is what $tau$ precisely measures.   This is a clever homage to the fact that $pi$ is the first letter of the Greek word for perimeter, which $pi$ (sort of) measures.
2. It looks a lot like the letter T, which is traditionally used to denote period, and the sine and cosine functions both have periods of exactly $tau$.
3. It looks a lot like the symbol “$pi$,” except with only 1 leg, which reminds the user that it only takes 1 $tau$ to go around the circle, but it takes 2 $pi$‘s to do it.

So, closing on that last idea… what symbol might you use to measure ’round the circle eight times?

Thank you, thank you. I’ll be here all night. Don’t forget to tip the gal who brought you pie.

This entry was posted in nerdify. Bookmark the permalink.