The science of bionics uses knowledge about how biological systems work to help solve engineering problems. The material Velcro, for example, was inspired by the way burrs behave when they stick to your clothes, and some computer chips are now wired in ways that imitate the "wiring" of the brain and nervous system. But in popular use, the adjective bionic almost always describes artificial limbs or other bodily parts that work as much like real ones as possible. A perfect bionic arm would move and function as easily as a real arm—a goal we're rapidly getting closer to.