If you have ever studied vector calculus, the idea is a straightforward application of Green's theorem. The discrete version is the 'shoelace formula'. https://

If you have ever studied vector calculus, the idea is a straightforward application of Green's theorem. The discrete version is the 'shoelace formula'. https://en.wikipedia.org/wiki/Green%27s_theorem https://en.wikipedia.org/wiki/Green%27s_theorem https://en.wikipedia.org/wiki/Shoelace_formula https://en.wikipedia.org/wiki/Shoelace_formula This kind of thing is one of the more important ideas from 19th century math/physics, and is studied by most STEM undergraduates in their first or second year.