Crop circles are now known to have been deliberately perpetrated hoaxes created by university students with no equipment other than a wooden board tied to a loop of rope, so that a person can trample down the growing grain by holding the board underfoot.

Despite the admissions and demonstrations of circle-making by some of the hoaxers, some people still claim that at least some crop circles cannot possibly be the product of any agency short of exraterrestrial intelligences.

The human mind's propensity to believe anything is remarkable.