How Exile builds a world

Exile (Superior Software, 1988) gave the BBC Micro something seemingly impossible: a single coherent world of 256×256 tiles with caverns, shafts, diagonal tunnels, a crashed spaceship, an underground base and all on a machine with 32KB of RAM, most of which was screen memory and game code. Stored naively, the map alone would be 64KB. Twice the machine. The trick is that the map is never stored.…