Bobbie The 3d printable Cartesian devil!

Gonna need people's help here, I'm brand new to 3d modeling and have no printer to work with, so it's all trial and error. The theory goes that if you print either of these two items, place them in a bottle of water, top it off and close the cap, then squeeze it will act as a proper Cartesian Diver (or Devil)

http://en.wikipedia.org/wiki/Cartesian_diver

I don't have the facilities yet to test this design, I'm hoping that the way i modeled it it should spin when you squeeze and release a