I believe the phenomenon is part of a directed electromagnetic energy system created to contain nuclear fallout as part of a missile defense system. If you are able to configure electromagnetic waves in a certain pattern, you can effectively contain certain elements in the atmosphere (think the ghost trap thingy from Ghostbusters).

What better way to test the complexity of electromagnetic patterns you can create than by using fractals? You punch in the mathematic equation into the computer and viola! sweet cryptic patterns appear in wheat crops. I believe the techs employed to use these systems have quite a sense of humor.

It's unclear to me whether or not these crop circles are a direct result of HAARP, or of a similar system located in the UK. Perhaps they are programmed from HAARP in Alaska, and the patterns are directed to the ground via satellite.