If you fold a pizza in half lengthwise to eat it (the proper way to eat pizza), then you’re actually utilizing mathematician Carl Gauss’s “theorem egregium” or the “remarkable theorem.”
Mathematician Clifford Stoll, over at the Numberphile YouTube channel, proves that pizza likes Gaussian curvature, while also giving viewers a mathematics lesson in the process.
Gaussian curvature reflects the combination of two distinct curvatures (such as on an x-axis and a y-axis). A cylinder, for instance, has zero curvature because while measuring in one direction produces an outward curve, the other way is flat. A sphere always has positive curvature.
By drawing all over food with a permanent marker, Stoll describes how certain foods like oranges, bananas, and bagels maintain curvature. However, things like pizza, which are partially flat, have zero curvature, no matter how you bend it. When you improve a slice’s rigidity by folding it, you’re experiencing Gaussian curvature.
If you don’t like pizza or math, at least you can get a look at what somebody who really loves math looks like. Take this from someone who really loves pizza.