If you check post 1 and post 8, you'll see that the black rectangle, when it got covered, was covered by a greeble that also covered the row of multicolored spaces beneath it. One would have to check to see if the greeble came and went, as post 8 shows an engineering mate checking it. Then again, it did move around engineering at least once, and that image may be from before it moved to its final space.