The group enters a room with a row of grandfather clocks. A message on the wall reads "DOOR OPENS AT MIDNIGHT"
The clocks are broken - their hands spin round and round.
Inside the clock doors, there are replaceable chimes.
The group pulls a lever nearby that causes a tune to play. Then, the clocks chime notes in succession.
The clocks that chime a note matching the tune will stop spinning at 12, and the face lights up!
The group orders the chimes in the clocks so that, in order, they repeat the same tune that plays when the lever is pulled.
Once the chimes match the tune and all of the clocks have stopped at midnight, the door opens!
The next group that comes in has a different tune to match, making for a state A/B reset. The first note between the tunes will overlap, to show users what happens when a chime is in the right place - people will hear that the first chime matched the played tune.