xkcd xkcd.com xkcd.com: A webcomic of romance and math humor.Coordinate Plane Closureon February 8, 2023 at 05:00 Electron Coloron February 6, 2023 at 05:00 Size Comparisonson February 3, 2023 at 05:00 Bursa of Fabriciuson February 1, 2023 at 05:00 Coordinate Plane ClosureElectron ColorSize ComparisonsBursa of Fabricius