LiveScience has an article about how the names were configured for the September 11 memorial. Math Keeps Friends and Colleagues Together narrates the search for a way to connect those on the memorial who were connected with each other in life.
There is special meaning for the North and South Memorial as well.
This is an excellent example of conceptual elements which are part of the Conceptual Age and, the more I read and think on this topic, the more I am sure that we are already IN the Conceptual Age.