Well..., I’ve of the opinion that if something is scientifically possible to be reproduced, it can be figured out and done. Thus, I don’t hold to the theory that it’s so much of a secret (in terms of scientific principles that we know about) that this can be “hidden” from others who know science, too.
The fact that it’s not being reproduced by others (in a demonstrable way and by way of a “test example”), simply shows that the knowledge from a scientific standpoint doesn’t exist in a normal and conventional way — or else — after a few decades of this, anyone with “half a mind” would have been able to do it with the measurable characteristics that we find in some of those crop circles.
I don’t believe that “secret societies” exist (no matter what we’re talking about, crop circles, the Illuminati, Obama’s birth certificate or the Bilderbergers) in which normal people can’t figure out something and show it to the world.
I'll be "wise" and say I don't know if "secret societies" exist.