Deus Ex: Mankind Divided - 12 Easter Eggs, Secrets & References You Must Find

11. The Weighted Companion Cube - Portal

Lastly for the Future-Past Antiky, journey further into this first room and head inside the pile of books to the right, as you'll come across a very familiar-looking cube.

This is Portal's 'Weighted Companion Cube', which Valve tasked you with using in a number of puzzles.

Sadly, here it can't be picked up or moved around, but answers the barmy fan theory that the cubes are filled with human remains.