Many people think that crop circles are result of UFO landing. They appears in darkest nights and we see their traces on grass fields. I will not dispute this opinion, because nobody contact UFO and wind of helicopter propeller looks more realistic reason of natural simple crop circles formation.
Inspired by natural crop circles enthusiasts croppers create own artificial crop circles. Often the more exact name for artificial crop circles is crop figures because they don't have rounded shape but more complicated. Croppers depict various types of figures such as polygons, fractals, artistic images. Every year contest of circle croppers is being taken at http://www.cropcircleconnector.com/
Below there are some examples of crop circles.
|Six ray stars||Julia set|
|Penrose triangle||Koch snowflake|