Doom 3 Easter Egg - Old Doom Box Art Reference

After killing Sarge, you'll enter another level where you need to find the PDA of P. Rogers to continue. Right before you find this scientist, there will be a room filled with 4 stone tablets that are being researched. If you notice the one on the far left, it almost exactly resembles the original box art/title screen for the original DOOM. The only exception is that the lead character is holding a cube, and the top/right corner of the tablet is cut off to where you can't see his face.