The map source code in this file is organised into several "visgroups", each
containing one of the major sections of the map. The "DEV" visgroup contains
items for testing parts of the map and should not be included in final builds.

This visgroup contains the following subgroups:

-  Blinds: used to blind off one of the major sections for separate testing;

-  Test rigs: contains items for stress-testing the various physics-based
   puzzles in the map.
