Gears embedded in business cards

In [Bre Pettis]’s latest “things” video, he talks with [Adam Mayer] about his geared business cards. [Adam] has designed several versions of these cards that have functional gear systems in them. There appears to be a simple two gear one and a more complicated planetary gear set up. The designs have been uploaded to Thingiverse, so you can download and build your own.