High Quality Content by WIKIPEDIA articles! Unconventional computing is computing by a wide range of new or unusual methods. It is also known as alternative computing. The different methods of unconventional computing include optical computing, quantum computing, chemical computing, natural computing, biologically-inspired computing, wetware computing, DNA computing, molecular computing, amorphous computing, nanocomputing, reversible computing, ternary computing, fluidics, and analogue computing. Historically, mechanical computers have been used in industry before the advent of the transistor. Mechanical computers retain some interest today both in research and as analogue computers. Some mechanical computers have a theoretical or didactic relevance, such as billiard-ball computers or hydraulic ones, and are actually simulated not really trying to use mechanic collisions of billiard balls. Domino computer is another theoretically interesting mechanic computing scheme.