Et in Arcadia Ego (19(85)94)

The 24 hour clock mechanism under the sundial revolves it once every 24 hours. It thus tracks the sun as the earth revolves, and the two methods of trying to read time cancel out.  The shadow stops still on the dial and gives the illusion time has stopped, which is always the illusion of art. 

"Et in arcadia ego" is a classical quotation written on a tomb perused by sheapherds in a famous painting by Poussin.  "I (death) exist even in Arcadia" might be the translation.

The piece must be exhibited outdoors. If it is not surrounded by (slightly formalised?) nature or gardens, 4 small conifers making a square around it might be good.