MUD (1980)

“Imagine you are playing an adventure,” asks an article in a popular computing magazine, credited to someone called Endora the Witch.

Let’s say you’re in a room of a house, you have found some treasure, and are now a bit stumped as to how to get it past the bookcase, which you can’t shift but which you’re certain conceals a secret passage. You have tried all sorts of commands to no avail, and are about to give up when up on your screen comes the message: “Tom has just arrived.”

Tom is “not part of...