1) 'airfield' 50% transparent, brownish single runway. Represents a simple packed-ground airstrip.
2) 'airstrip' concrete single runway.
3) (default airbase)
4) default airbase with an adjacent building
5) extremely low-walled fortress. represents a short wall of sandbags or wood to provide some basic defense
6) default fortress without a tower
7) (default fortress combines previous bg with next fg)
8) 2 tower fortress with 1 tower in front like default, along with another in the back
9) 4 tower fortress with 3 towers in front and one in behind, covering all 4 corners.
10) 'trench' (at the bottom right) a simple, but large trench, mostly with 50% transparency with some darker part toward the outside. Open to suggestions
