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 netherworid 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.

Since then, pretty and user-friendly programming tools have been developed. It's possible to program a computer now by sitting at your desk in the Metaverse and manually connecting little preprogrammed units, like Tinkertoys. But a real hacker would never use such techniques, any more than a master auto mechanic would try to fix a car by sliding in behind the steering wheel and watching the idiot lights on the dashboard.

Hiro does not know what he is doing, what he is preparing for. That's okay, though. Most of programming is a matter of laying groun............