Jay, ----- Original Message ---- I distinctly remember two of the projects. One was on the working of the heart. It was a board that tilted front to back on a triangular wedge. Routed into the board was a logical diagram of the human heart. The valves were one way metal flaps that opened by rotating on a thin metal shaft or wire. The blood was a set of marbles. When you tilted the board to the back, the marbles rolled through the valves in one direction, then when you tilted it back the other way the flaps only let the marbles go into the correct chambers. --- I remember that!!! I wanted to build it, but for any number of reasons didn't. For a long time now I remember associating the marbly heart with my ESR Dr. Nim toy, which used marbles to play the game of Nim. What I don't remember is which I came across first- Dr. Nim or the Marbly article. The idea of using marbles, tilt boards, gates, has been tucked away in my brain to some day emulate **something**. Scott ____________________________________________________________________________________ Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. http://videogames.yahoo.com/platform?platform=120121