“A method for inducing cats to exercise consists of directing a beam of invisible light produced by a hand-held laser apparatus onto the floor or wall or other opaque surface in the vicinity of the cat, then moving the laser so as to cause the bright pattern of light to move in an irregular way fascinating to cats, and to any other animal with a chase instinct.”
But this pales into insignificance compared with another one Quentin pointed me at. It’s U.S. Patent # 4,022,227: “Method of concealing partial baldness.” It describes “a method of styling hair to cover partial baldness using only the hair on a person’s head. The hair styling requires dividing a person’s hair into three sections and carefully folding one section over another. “ A diagram may be helpful here:
