We can't figure out most crop circles but what we do know is that they are not man made.
We're so used to the crop circle phenomenon that we include them in our draw full of the unexplainable and don't speak about them with such awe as when they began to proliferate in great numbers.
Crop circle experts are still analyzing and testing circles to understand how they are created and what they mean. It's clear that many of them aren't and can't be done by human effort. There are a bunch of fake ones though.