Fluidic logic

Fluidic logic is the implementation of Boolean algebra functions using streams of fluid (such as water or air). A jet of fluid can be deflected by a weaker jet striking it at the side. This provides non-linear amplification, similar to the transistor used in electronic digital logic. It is used mostly in environments where electronic digital logic would be unreliable (e.g., systems exposed to high levels of electromagnetic interference or ionizing radiation).

To build a flip flop, a nozzle is directed at a Y junction. A laminar flow of fluid will stick to one of the two sides. Weaker jets coming in from either side of the Y junction can switch the state of the flip flop.