And it has this symmetry. And a distribution like this, this right over here, a discrete distribution like this, we call this a binomial distribution. And we'll talk in the future about why it's called a binomial distribution. But a big clue, actually I'll tell you why it's called a binomial distribution, is that these probabilities, you can get them using binomial coefficients, using combinatorics. In another video we'll talk about, especially when we talk about the binomial theorem, why we even call those things binomial coefficients. But it's really based on taking powers of binomials in algebra. But this is a very, very, very, very important distribution.