Ethan wrote: Just a quick note for now. Resistive sheets belong to a category of analog computing called network analyzers. Fluidics (or fluid logic) can have both analog and digital processes. You can perform boolean operations, but you also can have fluid amplifers. --Doug ========================================= Doug Coward @ home in Poulsbo, WA Analog Computer Online Museum and History Center http://dcoward.best.vwh.net/analog =========================================