14 
Watching this cube slowly turn itself inside out as its internal gears mesh together is a mesmerising and puzzling experience. It looks like it should never work, but it does.
I have a degree in engineering. Hell, I have a PhD in engineering. I (kind of) know how it works. But it still looks like magic to me.
It’s of little practical use, sure — but it does illustrate how powerful 3D printing, the process used to create this thing of wonder, can be. The beauty of 3D printing is the way it can turn a theoretical, abstract idea into something tangible without the need for craft skills. In fact, in that vein, over at Thingiverse there’s a bit of a trend for using 3D printers to turn all kinds of solid shapes into complex gear systems.
Though I wouldn’t spend too long trying to design your own, because the 3D CAD files are freely available online. Now all you need is a 3D printer. [Cube Gear via Boing Boing]
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I think my brain just melted trying to figure out how that works.
My mind just assploded :/
Though the ones at thingverse are; the cube in the video isn’t 3d printed, it’s made of paper. No 3d printer needed, you can download the plans and print your own here:
http://paper-replika.com/index.php?option=com_content&view=article&id=5119:gear-cube-papercraft&catid=109&Itemid=200741
I made one a while back as a gift for a friend. Other popular ones are the gearheart and gearsphere papercraft, which are mechanically similar.
Transformers
Is it bad that I took one look at that and understood it instantly?
I need to get out more.