The 4 Seasons

~ Jean-Robert Valentin

Spring…

Summer…

Autumn…

Winter…

…Loop

https://upload.wikimedia.org/wikipedia/en/5/5f/The_Mandelstam_identity.jpgGraphical representation of the simplest non-trivial Mandelstam identity relating different Wilson loops.

Source: https://en.wikipedia.org/wiki/Wilson_loop