Geneva Mechanism

Geneva Mechanisms have been used in old time movie projectors, to provide advance and hold for the 35 mm film. Some very nice mechanisms for cell phone cases have been constructed
and published on Thingiverse (and elsewhere), for users to fiddle with during boring telphone
conversations, and even a couple of stand-alone stls have been published. This has inspired me to model the mechanism in Openscad, mainly for learning the program. Also included is a video of the operation of the gadget. If