Crop circles is a term use to describe patterns created by the flattening of crops such as wheat, barley, rapeseed (also called "canola"), rye, corn, linseed and soy. The term was first used by researcher Colin Andrews to describe simple circles he was researching. Since 1990 the circles evolved into complex geometries, but by then the term had stuck. Examples can be found worldwide. Various hypotheses have been offered to explain their formation, ranging from the naturalistic to the paranormal. Naturalistic explanations include man-made hoaxes or geological anomalies, while paranormal explanations include formation by UFOs. Many circles are known to be man-made, such as those created by Doug Bower, Dave Chorley, and John Lundberg, and a 2000 study into circle hoaxing concluded that 80 percent of UK circles were definitely man-made.