UPDATE: I am very sorry if I misrepresented this thing as I've numerous complaints that this thing is not perpetual motion, some being quite hostile. This thing is an illusion and was meant for entertainment purposes only and as such is not perpetual motion. My sincerest apologies to those who believed I was indicating that this thing truly was perpetual motion. It's just an illusion that, unfortunately, has upset a few people here and on YouTube. Again, my sincerest apologies to those offended by the post of this thing. Perpetual motion on your desktop! Video here: https://www.youtube.com/watch?v=LoYZ07guQCg. Video of prototype here: https://www.youtube.com/watch?v=Al6UfIEhsWs. Will larger ball bearings will make it spin faster? In the instructions for RichMac's version, he stated "Perpetual motion doesn't seem to work, what am I doing wrong?" Well, I think I discovered the answer (see instructions)! Designed using Sketchup 8, printed in PLA on a Makerbot Replicator 2 using Makerware 2.3.3.42 "Standard" settings.The answer is add a motor, drive wheel and a perpetual supply of batteries. Study "Assembly.skp". Obtain the following parts: 1) Gear Motor - "6VDC 45 RPM Pinky Finger Sized Gear Motor 1" Long x 15/32" x 3/8"" from either amazon.com or directly from http://sciplus.com/p/MICROMOTOR_47952. 2) Single "AA" batter holder - Radio Shack part number 270-0401. 3) "AA" battery. 4) 8 9.5mm (3/8") ball bearings - I found mine at Ace Hardware. 5) Rubber band, 1mm thick by 4mm wide. Solder the red wire from the battery holder to the gear motor "+" terminal. Solder the black wire from the battery gear holder to the motor "-" terminal. Print the PLA parts. Break the hold down disks off the corners of "Base.stl" and "Top.stl". The drive wheel assembly is similar to a car wheel / tire assembly where "Wheel Motor.stl" is the wheel, and the rubber band is the tire. Start by cutting open the rubber band such that after the cut it is a strip. Place a small dot of thick cyanoacrylate on "Wheel Motor.stl". Press one end of the rubber band onto the dot and hold until it sets. Roll the rubber band smoothly around "Wheel Motor.stl" until it meets the beginning, then cut it to fit. Place another small dot of thick cyanoacrylate on "Wheel Motor.stl" where the end meets the beginning, then press the end in place and hold until until it sets. Press the drive wheel assembly onto the gear motor shaft. Place the gear motor assembly and battery holder in "Base.stl". Test fit "Axle.stl" in "Wheel.stl", making sure the wheel rolls smoothly on the axle. If not, use a 5/32" drill bit (in reverse), file, and/or modeling knife to carefully enlarge the hole in "Wheel.stl" until it does. Place "Axel.stl" in "Wheel.stl", then press into "Top.stl". Place battery in the battery holder, then press "Top.stl" onto "Base.stl". Place ball bearings on the wheel. If you are interested in additional instructions on how the video was made, feel free to comment. Enjoy!