The prisoners' game

Down in the dark there are honours, and a scoreboard. Praise goes to whoever is quickest to spot the passing shadows, best at remembering which came before and after and together, and cleverest at guessing what will come next.

The sharpest joke in the dialogue, and the app makes it playable. There is real expertise in the cave. It is genuine skill, genuinely predictive, and completely worthless — and anybody who has ever been very good at something inside a system they had not questioned should feel the point land.