The Atlantic The mathematician Jordan Ellenberg discusses gerrymandering, bad COVID-19 projections, and how geometry explains the world. About the author: Derek Thompson is a staff writer at The Atlantic, where he writes about economics, technology, and the media. He is the author of Hit Makersand the host of the podcast So you’re walking down the street carrying a hot slice of pizza on a paper plate. The tip of the slice is so heavy with cheese and sauce that it’s drooping toward the ground. How do you solve this problem? Naturally, you fold the pizza lengthwise, New York–style. But...