Some kind of combination lock. The player seeks a physical object or he seeks information. But right now I'm talking about combination locks. The point of a combination lock is that it has too many combinations for the player to try. You either use a lot of combinations, or you mess with the player every time he gets it wrong.
ROTS has many combination locks.
Nearly every puzzle, in fact, is a combination lock. Most of the locks have a lot of combinations. The last puzzle of the game has just six. And if you get it wrong, the game kills you. I really don't know why the designers thought this was clever.