The GUI was designed to evoke the idea of military vehicles and equipment. This was achieved by emulating the angular, rugged, and weathered look of the Abrams Tank. Soldiers would quickly identify with it because their surroundings are filled with objects that share the same color pallet and general appearance.
The Ordnance Corp logo is used in the upper left corner to indicate that the course has been built for the Ordnance Training Division of the Army.
Click the image above to see a short video showing a typical rollover interaction that uses photography, and illustrated elements.