Leonardo first noticed the relationship between the passage of time and the number of rings on a tree cutting.  These growth layers are now known as "yearly rings."  In the painting "Current" the correlation between time and rings is interpreted as a stream that inevitably carries man in one direction.

The Theater of Dionysius was the main Athenian theater under the open sky.  Named after the god of wine and fertility, it was built at the foothill of Acropolis and was a place where various festivities and drama performances took place.  Here, we can invoke the metaphor of the growth rings by saying that the dramatic works of Aristophanes, Euripides and Sophocles came to us through the layers of Time.