Forerunner symbols

In the Halo Universe, there are signs above doors, on Elite armour, virtaly anywhere on the halos, and in the Covenant.

According to Bungie, namely 'Joseph Staten', the blue and red signs mean a 'safe zone' as in whether or not the Flood are there.

Symbol Analysis
Taking a closer look at the symbols and where they were found and what has been said by Bungie we can deduce the following:

 image:Forerunner_Symbols_2.png|The glowing cyan ones are found on the control panel in the Halo control room. image:Forerunner_Symbols_3.png|The symbol on the left, the non-glowing cyan one, is found on the back of the higher-rank Elites. The yellow one is found on the Covenant plasma grenade. image:Forerunner_lift_Symbols.png|We can deduce that the purple symbol means Elevator or Lift or something similar, most likely, as it is seen above any door leading to one of the elevators in 343GS. image:Forerunner_flood_warning_Symbols.png|Above the doors where large Flood storage rooms are, two of the red symbols always appear, which backs up what Staten said about red and green symbols. 

All the others are found in various Forerunner structures, mostly on the level, 343 Guilty Spark (Level).

Croped Symbols Analysis
Several of the symbols are variations of each other. There are a total of 16 unique symbols; the other 8 are rotations or croppings of the 16 main symbols. Of note is the fact that the cropped versions may not have been intended to be cropped. They appear on a wall or something, similar to the non-cropped version, but they are placed (as decals) in such a way that part of their texture extends past the edge of the poly that they are on, thus clipping it off. But, in sake of being thorough, I have included them as separate symbols.