Touring Complete Plumbing is a graphical simulator that uses water pressure and pressure activated valves to implement digital logic functions. This was intended as an educational tool.
The user can drop down various types of primitive valves and connect them up with pressure sources and pipes to construct digital or analog systems.
tcPlumbing includes a library of pre-built circuits such as adders, oscillators, and latches. The user can also create save, and load their own designs