Cocklebur Hooks In 1941, a Swiss engineer was taking a walk in the woods. While out for a st George de Mestral found some cocklebur seeds sticking to his clothes. He tried to brush them off, stuck onto the wool of his clothes. Back home but they he examined the cocklebur seed under a microscope. The cocklebur was a plant comprised of an intricate, yet simple, combination of tiny seeds with thin strands or hooks. In the plant world, these hook are called burrs. They easily attached themselves to anything that brushes by. If an animal walks by, its fur catches onto the plant. De Mestral discovered that the concept of two opposing burrs or hooks could be used to make a fastener.