Crop circles are patterns of a circular nature that unexpectedly appear in cereal crop fields. Most frequently seen in fields of Southern Britain, they have been reported world-wide.
While many occurrences can be explained as pranks, many others are as yet unexplained. The patterns range from simple circular patterns into huge and complex, geometric formations.
See http://cropcircleconnector.com and http://www.circlemakers.org for further information.
If you're interested I suggest going to http://www.google.com/search?q=crop+circle+mandelbrot
Note that most of the features that have been claimed as "mysterious" about crop circles have been detected in circles known to be manmade.
Note that the farmers responsible confessed and gave a demo of how they make them. The mysterious thing is people wanting so much for there to be something mysterious about crop circles that they do not believe the people responsible. All occurrences can be explained as pranks.
I've been measuring this crop circle for three years, and the strange this is: the circumference and radius change, but the diameter stays the same. ... Another funny thing is that when you stand inside this circle, the weather never changes. It's always 43 degrees Fahrenheit, with a 40% chance of rain.
- from the film Waiting for Guffman
Crop circles show just how easily people can delude themselves into believing anything they want to believe.
I recall one of the Universities studying crop circles had an infra-red camera focused on a wheatfield every night. One morning their film showed people tramping down the wheat with boards tethered by rope to posts inserted into the ground at the centre of each circular part of the crop circle pattern.
In other words, just the way that you or I would make a crop circle design if we were given the job.
So what did the researchers say? Did they announce that the research project was called off because it was obvious that these crop circles were just a prank? No, they issued a press release denouncing the larrikin behaviour of the wheat-trampers, who they said were trying to make a mockery of their serious experiment to find the real cause of crop circles.
I must confess I'd really enjoy making a crop circle myself, if it weren't for spoiling the farmer's wheat. Some of them are real art of the most fantastic kind.
Compare Snow and Ice Circles - http://uk.kornsirkler.org/relaterte_fenomen.htm
See also LifeOnOtherPlanets