It is one in the morning in Memphis, Tennessee.
Most of the city is asleep. But out at the airport, something extraordinary is happening.
Planes are landing. Not a few. More than a hundred, one after another, stacked up in the dark.
Gif by Sogedim on Giphy
They taxi in, get unloaded, and enormous quantities of boxes pour into a sorting facility the size of a small town. Machines read labels. Belts carry packages for miles. Everything gets rearranged.
Then, a few hours later, the same planes take off again, loaded differently, headed everywhere.
By the time you wake up, the thing you ordered yesterday afternoon is on a truck near your house.
That entire system exists because of a college paper, a bad idea about weather, and one brilliant piece of geometry.
Let me show you.