Riff must think people are idiots. " No, it is not possible. Mere humans can't do it. They cannot do crop circles, because they are too complicated."
Riff, you and I might not be able to do it, because we are too damn stupid. That does NOT
mean no-one else can.
Take Stonehenge. Lot's of crackpots have claimed that aliens must have been a part of building Stonehenge, since primitive people could not do it. Well, watch the following video, and tell me that! http://www.youtube.com/watch?v=lRRDzFROMx0