Etruria is the Italian word for Tuscany. The sculpture was inspired by an Etruscan bracelet I saw in the Archaeological Museum of Florence. In my interpretation a set of arcs form the top and bottom. They are, if connected, actually sections of the same circle. The sides are arcs from a larger circle whose center lies outside the sculpture. The small locking piece section was added to make the work more interesting. Its proportion is the thickness of the circle.
There are several versions of this particular design. The original was about 18'' tall. The largest is 10' and is sited in front of the State Office Building in Trenton, NJ.