http://www.chiefdelphi.com/media/papers/1306
Gives you this:
http://www.chiefdelphi.com/media/photos/13413
Not sure if any of any of those components are legal nowadays (we used it in 2002) but it's pretty easy to make with limited resources, and it's from Baker's team originally so you know it was probably the inspiration behind some of the AndyMark stuff.