Recently I paid a visit to Matthias Wandel's woodworking site on the web. I discovered this site back when I was building Mindport's pipe organ, and found a number of useful ideas that I incorporated into my instrument. It's a good place to look for exhibit ideas, not to speak of a large collection of esoteric woodworking wisdom. Upon looking through the various wooden gadgets that Wandel has designed, I ran across plans for an operating combination lock mechanism, all fabricated from wood. For $7 I downloaded these plans and built my own version, which you can now explore at Mindport.