Understanding the Sentence

I am a huge proponent of diagramming as a means of understanding the way words, phrases, and clauses are related to one another in a sentence.  I believe it is one of the principal tools that allows the mind to fully grasp the logic of language and sentence structure.   I found a wonderful site several years ago and keep forgetting to share it with all of you language nerds and/or teachers. 

Read this sentence from the first pages of Nathaniel Hawthorne's The Scarlet Letter, then examine the diagram below to see the logical and grammatical relationships within the sentence:

In my native town of Salem, at the head of what, half a century ago, in the days of old King Derby, was a bustling wharf--but which is now burdened with decayed wooden warehouses, and exhibits few or no symptoms of commercial life; except, perhaps, a bark or brig, half-way down its melancholy length, discharging hides; or, nearer at hand, a Nova Scotia schooner, pitching out her cargo of firewood--at the head, I say, of this dilapidated wharf, which the tide often overflows, and along which, at the base and in the rear of the row of buildings, the track of many languid years is seen in a border of unthrifty grass--here, with a view from its front windows adown this not very enlivening prospect, and thence across the harbour, stands a spacious edifice of brick.  

(click photo to enlarge)

Is this fun or am I a nerd?  I'll accept a YES on both counts.