Escape rooms
When I was reading Room and the first time I realized that Ma was kidnapped and held as a sex prisoner, I first thought of escape rooms, which started becoming popular around the world starting around 2015. In an escape room, you are stuck in a rule filled with objects (some are hidden), and some of these objects are clues to how to escape the room. Room however has no hidden objects (at least according to Jack), and no clues to escape the room (except the code, but there are no objects that can help crack the code). And in a "regular" escape room, you have a time limit (less than 1 hour in most escape rooms) to solve the puzzle, and if you can't solve it in time then you just lose, and you just leave the escape room and mope for the rest of the day. However, if Ma and Jack are not capable of escaping Room within a time limit (which is the time Old Nick leaves the Room and the time Old Nick arrives again), then Ma has to suffer another night with Old Nick and Jack has ...