It's pretty convenient (on Ubuntu) to be able to move windows around desktops. Apart from the usual Super + Arrow keys to manage windows within a desktop, you can use:
Ctrl + Alt + Left/Right Arrow: Move desktops
Ctrl + Alt + Shift + Left/Right Arrow: Move window to desktop
Super + Shift + Arrow: Move window to another monitor
Super + Drag: Drag window from anywhere
How Diffie Hellman Key Exchange Works by Julia Evans is an excellent explanation. Share a random number. A multiplies it by their private key and shares SA. B multiplies it by their private key and shares SB. They multiply the others' key with their secret key and they get SAB = SBA. Now both of them have the same new secret they can encrypt/decrypt with, but no one else knows, even though they shared everything publicly! This may be one of the best cool uses of math I've seen in a long time.