These signs predate the NYPD's most recent Model Block program (found to be unconstitutional in 2002), but they probably denote something similar.
They probably convey important information to other aliens unfamiliar with the area, like where the bathroom is.
Helps protect the bark from rapid temperature change on sunny winter days
Ground was broken for this library 100 years ago, but it wasn't completed until 1940. (1940 - (2012 - 100)) = 28!
I love that the library website has an entire page devoted to the inscriptions on this building!
