The jury is still out on what exactly causes or who creates crop circles. Some believe that electrically charged air currents are responsible and others blame aliens. Humans have claimed responsibility for making some of them using a rope and a plank-like tool. More theories include downdrafts stirred up by helicopters or small planes, swirling winds, and electromagnetic radiation.
Crop circle designs include the single circle, circles in sets of 2, 3, or 4, and circles inside a thin outer ring. Some patterns have been of mathematical equations, flowers, words, smiling faces, and ancient pictures. The creations can be anywhere from a few inches to a few hundred feet across.
Mysterious crop circles were reported in July 2012 in eastern Washington state just 10 miles south of the Grand Coulee dam, the largest hydropower producer in the U.S. You can see the circular patterns of flattened wheat just off Highway 174, about 5 miles north of the town of Wilbur.