In his regular life, graduate student Matt Springer teaches undergraduates the basics of physics: the mechanics of heat, rotational motion, the relationship between kinetic and potential energy, and more. Matt takes a similarly instructional approach on his blog Built on Facts, walking readers through equations and concepts that might have grown a bit fuzzy since their own undergraduate physics courses. In his latest series, Matt looks at each of James Clerk Maxwell's four famous equations describing the laws of electromagnetism. "It's difficult to conceive of much more impressive physics," he concludes, "but I'm an optimist. Physics is not yet out of surprises."