Over millions of years of evolution, nature has worked out solutions to many problems. Humans have arrived late in the day and pinched them. For example, Velcro was invented after a Swiss engineer marvelled at the burdock burrs that got stuck to his dog's fur; the idea for robotic arms came from the motion and gripping ability of elephant trunks, and the front of Japan's bullet trains were redesigned to mimic a kingfisher's streamlined beak, reducing the sonic boom they made exiting tunnels. There are different types of mimicry, the most straightforward is the simple idea of copying something that exists in nature. Buildings are an obvious example, as outlined by research published in Nature.