In C=AB, A (input) is the slider to the right. Control it with W and S.
B (input) is the sider at the bottom. Control it with A and D.
The left sider is the output.
These were used in mechanical computers, for example fire control
computers onboard war ships. The third slider (c) would have a rack
as well, connecting to an output shaft. The scale of the output is not
the same as the inputs, this could be rescaled using a simple one- or
two-stage gearbox.
Update1: (hidden) Mechanical limits added to the racks. Thanks Xray!
I'm planning to update the indicators to dial indicator style, but
maybe that defeats the purpose of showing the beautiful close relation
between a simple mathematical formula and geometry.
Update2: I preloaded the double-pinions driving the racks. The larger
cog wheels are for easier manual manipulation, plus I'm working on
something...
Please rate!