The Solarbotics GraviTrack Battery Marble Machine Kit
Elegant, swooping hands pass marbles to each other to the top of a sweeping multi-level track. A switched battery pack smoothly exercises the mechanism. The smooth pick/hand-off/place motion is hypnotic and enchanting. No soldering is necessary.
Measuring approximately twice as wide as our original Solar or Battery Marble machine kits (at 250 x 127 x 140mm, or 10" x 5" x 5.5"), the GraviTrack is still desk-top compact but large enough for easy mechanical assembly.