This corridor-like space is part of my Deep Ocean Explorer: it is designed to act as a workspace in the submersible's lower deck area. The black flooring indicates that the item must be rotated on one axis so the flooring is on the bottom. (See my catalog for additional parts) Simply put for this to work be advised of which part goes where; the rest is of course your choice. There are two sets of workspace pieces both defined by what plane acts as the floor (this is self-explanatory).