Brann, Eva, "The Music of the Republic," The Music of the Republic: Essays on Socrates' Conversations and Plato's Writings, Philadelphia: Paul Dry Books, 2004, 108-245.
Survey of Arguments
A. The Republic is composed of concentric rings encompassing a center. 
B. The outer ring represents Socrates’ descent into the house of Pluto-Cephalus (Books I and IX-X).