After "Green Lantern" v.5 #25 was released, the creative minds involved (Geoff Johns, Ethan Van Scriver) were interviewed about the other, newly-introduced corps.  
 
One of the questions commonly asked was about the corps symbols. They promised that the answers would be revealed one day. After "Blackest Night," readers, if they remember, still don't have this question answered. 
 
Yes, there has been an explanation as to what inspires these symbols... 
 
- The Red Lantern Corps symbol is the outline of a Manhunter's chest. That makes sense since the Manhunters killed sector 666 which left the Five Inversions, including Atrocitus, as survivors.
- The Orange Lantern symbol are lines pointed selfishly inward to resemble a little fat man. That obviously tying into avarice.  
- Despite it being retconned, the Sinestro Corps symbol comes from Hal's Parallax armor.  
- The Green Lantern symbol is well-balanced or a siren, as some people call it.  
- The Blue Lantern symbol is supposed to play off the Sinestro symbol and looks like an angel.  
- Indigo's symbol has the arrows going outwards. It plays off the Orange symbol.  
- The one that doesn't fit, the Star Sapphire Corps, is just their old symbol with a change - the circle. 
 
That's the tie. They all have circles. Even in that above picture (which is what got me thinking about the symbols again), you can make out the watermarked circle and a piece of each color's symbol. The circle is also prominent in 3 of those embodiments. So I guess, the point of this blog (aside from racking up quest points) is to ask what do people think that circle means? Does it have any meaning or should I keep my late night induced thoughts to myself?

i think it has a circle shape maybe cause life is never ending but i like the blue red and orange symbol
Blue-embraces or kind of looks like it 
Red - comes from beneath and goes out from above can not be trapped 
Orange- looks like a big mouth 

That was very informative, thank you.