The Engraved Cube was a cuboid object that reaveals itself inside the movie projector inside Alan Morton's Office, after inserting the glass prism and watching the movie reel of Alan experimenting on his father. It was engraved with the words "LIBRARY 3D MAP" as well as some numbers that when used on the false books on one of the shelves, it opens a secret space within one of the book shelves, which includes a lever that reveals the holding tank that contains the Elder hybrid.