Mechanized Reasoning

I recently came into possession of a copy of an old paper (1951) that described a relay-based custom computer which enumerated arbitrary boolean expressions. It's pretty damned interesting and well worth a read:
http://history.dcs.ed.ac.uk/archive/docs/mechanized_reasoning_screenres.pdf

I think it would be a fun project to write a graphical emulator for this (or even better, build a real one from relays which you can get cheaply and easily at Radio Shack).