Hiro is messing around in Flatland. He is doing this partly to conserve the computer's batteries; rendering a three-dimensional office takes a lot of processors working fulltime, while a simple two-dimensional desktop display requires minimal power.

But his real reason for being in Flatland is that Hiro Protagonist, last of the freelance hackers, is hacking. And when hackers are hacking, they don't mess around with the superficial world of Metaverses and avatars. They descend below this surface layer and into the netherworld of code and tangled nam-shubs that supports it, where everything that you see in the Metaverse, no matter how lifelike and beautiful and three-dimensional, reduces to a simple text file: a series of letters on an electronic page. It is a throwback to the days when people programmed computers through primitive teletypes and IBM punch cards.

Neal Stephenson: Snow Crash 1992 Penguin Books London pp327-328