“I’ve got pi here, and I’ve got pi there; I’m pi-winning!”

Yes, that’s a Charlie Sheen reference which will almost certainly be lost on any future readers of this post. Oh well, such is life. And this post is not actually about Charlie Sheen; it’s about math! On [Pi Day][1] 2011, the ever ardent [Vi Hart][2] posted a video explaining why pi is wrong, and why we should all be using a new constant—tau, equal to two pi—instead. The argument, alluded to by Vi and elaborated on in [Michael Hartl][3]’s [Tau Manifesto][4], is surprisingly convincing, and it’s one which I—a math major who has yet to develop a good intuitive understanding of trigonometry—find rather interesting. Of course, pi has long been deeply entrenched in mathematics, and it seems unlikely that Pi Day will give way to the less mnemonic [Half Tau Day][5] any time soon; however, all change must begin somewhere, and that beginning cannot come until people understand what’s wrong with the current situation. Watch the video, read the manifesto, and decide for yourself. P.S. Here’s a bonus math doodling video for those who clicked through to read the full post. 🙂 P.P.S. For what it’s worth, [like the vast majority of original YouTube content][6], these videos are not currently captioned. 🙁 [1]: http://www.piday.org/ [2]: http://vihart.com/ [3]: http://www.michaelhartl.com/ [4]: http://tauday.com/ [5]: http://halftauday.com/ [6]: http://bcat.name/posts/my-final-project-for-intro-to-new-media/