Today is Pi Day. While some people might say that Tau is more relevant than Pi, it’s still Pi Day. With that in mind, you may want to wish your friends a happy Pi Day. And while that’s cool, it’s even cooler to wish them a Happy π Day (OK, well, it may or may not be cooler to do this, but it’s definitely geekier!). We’ll show you how to get the π symbol by adding a Greek keyboard to your iPhone.