This large, fake rock was used in episodes of Enterprise. It is constructed of painted foam. My rock looks very much like the rock on the top left of the pile in this scene from "The Forge". When you look at my rock straight on from the front you cannot see the curves shown in the photo above, you can see only one flat surface which seems to screen match to the rock in the screencap. Captain Archer and T'Pol helped stack these rocks at the cave entrance to protect themselves from a desert sandstorm.
