It has this
unusual "FLORENCE" ball clock that has a pendulum that swings freely back and forth once each second for one hour. Then a steel ball is raised and released. The ball follows a zigzag path pushing against pins on the pendulum thus pushing the pendulum to swing a little faster. Though the builder of the clock doesn't discuss the power source, I assume that it's an electric motor or solenoid, since he talks about an optical sensor being used to count the swings and then turn the hands.
He also shows a number of similar clocks that he's built.
http://www.betrisey.ch/eiroll.html
He has some video files showing the mechanisms in action. They're not YouTube videos, so you'll need software to view AVI files.
The CHRONOLITHE, a clock with a pendulum driven by light only:
http://www.betrisey.ch/echronolit.htm
