In digital systems we represent ... the apostrophe indicates the negation. The switch diagrams help clarify these rules but we’ll switch to logic gates now to use a more modern representation.

The diagram may serve, for example, to improve the interface coordination between a designer of pneumatic circuits, or may simply provide a symbolic functional system description to a plant manager.

Octobot mechanical and electrical analogue circuits (credit: Michael Wehner at al./Nature) As shown in the diagram, the fuel is a liquid hydrogen peroxide (H2O2) which the oscillator gets from one ...