Aerial view of a crop formation on Preshute Down, Wiltshire, England. Crop formations are patterns of flattened plants in crops such as wheat or barley. They started appearing frequently in the mid-1980s in south-west England. Their cause is unknown. Many theories exist, ranging from science-based physical explanations such as the insplasma vortexins theory based on the phenomenon of electrohydrodynamics (EHD) to unorthodox suggestions that they are created by extraterrestrial intelligences. centre ring with bar and circles, square at one end of bar