This will reward them with the other crystal. At any one of these intervals, the player is able to open the clock and solve the puzzle inside. By observing the clock face with the eyepiece, the intervals are more clearly visible, marked in blue. The other crystal is located within the grandfather clock in the Study, and it can only be accessed every 15 minutes in real time (on an hour, quarter past, half past, and quarter to). This will shatter the table that the safe rests on, and send the safe falling down into the Altar Room. By rolling the dome back and forth, the player is able to swing a large pendulum at the center of the opening until it hits the railing on the opposite side. On the far end of the balcony railing is a small golden dome. One of the crystals can be found in the safe of the Elevator Room. In the Conservatory, the player may observe that one of the scientific instruments on the back table has a wheel with three slots. The path to this artifact is a crystal collection quest. After it is used, it will remain in the player's inventory for the rest of the game, minus The Observatory. It must be used to transplant a mechanical part from the Study to the Elevator Room during the activation of the last doorway machine. The screwdriver is picked up as the player naturally progresses through the game. They can be achieved in any order, but can only be completed incrementally, as different rooms become available to the player. There are two paths the player can take individually, and unlocking either or both of these provides them with the necessary items. The player requires certain items in order to change the ending they receive.