My GF wanted an owl clock with moving eyes, so I designed this.

I used this ring model as my base design  http://www.thingiverse.com/thing:381615

you will need a battery operated clock with a pendulum (or glue the eyes in place if using a clock without a pendulum) 

this model is scaled to a clock with a minute hand measuring 53mm

Due to size constraints, I had to print this in 4 pieces, then assemble.

The complete assembled model included is for reference purposes to help visualize the assembly.