Bionics is the science of nonliving systems which function in a manner resembling living systems and of designing artificial systems which have the desirable characteristics of living organisms. These systems may simply be imitations of nature, such as military vehicles with jointed legs, or , more profitably, systems that embody a principle learned from nature. Examples of the latter include radar, inspired by the echolocation system of bats, or the development of associative memories in computers as in the human brain.