Sears Merritt on safe leads in basketball, expanding on Bill James’ method for telling when a lead is safe.
Kevin Jamieson makes a two-dimensional map of styles of beer. I’d like to see this for wine.
You can buy a 3D-printed triple gear (three gears which touch in pairs and yet can all turn simultaneously! or
read about how Saul Schleimer and Henry Segerman figured out how to make one.
Ben Orlin, a math teacher, writes about what it feels like to be bad at math.
chartsnthings made some charts of skill and chance in the NFL draft.
Melinda Theilbar explained how folklore can be dangerous to one’s business.
Ravi Vakil wrote about the mathematics of (a certain kind of) doodling.