What Crop Circles are made by aliens?

Everyone has always believe that crop circles are made by aliens. But that isn't entirely true. Since, no one has really seen an alien do it, there is no way possible to know that aliens are behind this phenomenon. But, humans are more than capable to make a crop circle. All it takes is a lot of practice a corn field ropes and a board and precise measurements and a crop circle can be made. In the movies it always appears that aliens are behind this event. So there you have it, Crop Circles are not, as so many have claim, attempts at some type of communication by aliens. They are made by humans.