I'm always amazed at the speed of these guys. Top guy got it all done in an hour. I don't know if they are geniuses or if they practice this stuff every day.
Mathematics is like a fractal, given some axioms it explodes into an infinite set of true equations. No one has to observe math for it to exist. I think our universe(s) could be the same way, given some natural laws, or equations, everything we know is defined to take place. Why would there have to be anything 'running' the simulation.
:e .
Will show a directory listing, you can navigate the directory tree and open files. Particularly useful if you have a shortcut to change the working directory to the current buffer's file path.