This version of the Marblevator Mini series features a seesaw and basin. The seesaw directs alternating marbles to alternating ends of the basin. Video of prototype here: https://www.youtube.com/watch?v=RuKmjNzfECM. Note the sign is not included, it was simply used to accentuate the seesaw motion. Designed for use with multiple marbles. Designed to use the base assembly of the Marblevator Mini here: http://www.thingiverse.com/thing:286045. Simply push out the worm gear and Bowl Track, then snap on the Seesaw track and replace the worm gear. And finally, if you don't mind manual labor, the hand cranked version is here: http://www.thingiverse.com/thing:310488. Designed using Sketchup 8 and printed in PLA on a Replicator 2 using Makerware 2.3.3.42. "Track.stl" and "Basin.stl" were printed "High" resolution, the remaining parts printed in "Standard" resolution.See the instructions for the Marblevator Mini here: http://www.thingiverse.com/thing:286045. If you already built the Marblevator Mini, you can use that base for the Seesaw Edition. "Assembly.skp" contains additional assembly notes. Depending on your printer settings, you may need to file and sand the areas indicated for smooth operation.