The Player of Games (Culture, #2)

by Iain M. Banks

As well as being a physical maze, it is constructed to be what one might call a moral and behavioristic labyrinth as well (its external appearance offers no clues to the internal lay-out, by the way; that’s just for show); the prisoner must make correct responses, act in certain approved ways, or he will get no further, and may even be put further back. In theory a perfectly good person can walk free of the labyrinth in a matter of days, while a totally bad person will never get out. To prevent overcrowding, there’s a time-limit which, if exceeded, results in the prisoner being transferred for life to a penal colony.”