One of my favorite books as a child was called Flatland: A Romance of Many Dimensions. Written by a grade-school teacher in 1884, it’s a novel narrated by a square who lives in a two-dimensional world ...

The last time I looked at random walks, I used them to calculate the value of Pi for Pi Day. But what is a random walk, really? A mathematician will tell you that it's a stochastic process—a path ...