Skyport

Ex-pneumatic clock.

It began life as a pneumatic clock. A ball fell every full hour inside a glass tube, the air under the ball was channelled through a hole to blow on the pendulum and give enough energy to the pendulum to make it swing for another hour.
In 2010, it also received electromagnetic propulsion: you could then choose between the two versions.
In 2020, the pneumatic propulsion was forgotten and it now only works in electromagnetic mode.