I'd have to agree with a sattelite based system. I think about six to eight months ago I posted an opinion of a type of sattelite pulse beam, programmed to fire specific adjustable patterns (like firing through a template). These newer circles are getting a little too exact to be anything else; and with so many people watching for their appearance, I'm sure someone would have a video tape of a UFO by now if this was an attempt of contact by an ET.

Then again, I could be wrong.