Ejercicio de cercanía II (Closeness exercise II) Work detail

The work consists of an electric engine that makes a magnet spin behind a mirror. The magnet drags a nail on the surface, generating the form of a perfect circle. This action continues eroding the glass surface and wearing away the nail at the same time. The piece keeps working constantly and indefinitely, while two materials compete and move over time, one acting permanently, while the other is only able to resist.