Coleridge's "Limbo" – Another ring composition?

This is from July 31, 2016. I'm bumping it to the top because we need a reminder of poetry.

While wandering in cyberspace, as I am sometimes wont to do, I came across a most curious, and thus alluring, blog: Samuel Taylor Bloggeridge. What a peculiar name, thought I, not realizing that this particular locus solus belonged to my old buddy from The Valve, Adam Roberts. Really though, thinking in retrospect, who else could it be? "Bloggeridge" indeed!

But then, Ted Nelson coined the term and birthed the concept of hypertext as an antidote to the (drug-induced) memory loss that (supposedly) gave us "Kubla Khan", did he not? He even called it Project Xanadu, long before Olivia Newton-John sang the song and did the movie (which has Gene Kelley's last film performance). One can only imagine how STC would tear-ass about cyberspace were he alive today.

In any event, and getting back on track, I'd come across a post Adam had written about "Limbo", one of STC's many poems that I have not studied. He wrote about it in a most tempting way. Thus:

The first thing to say about 'Limbo' is that its 28 lines divide into a central 12-lines section flanked by two paired 8-line sections, the first a kind of introduction, the second a sort of summary. What the two outer passages frame is a central image of 'human Time' as an old, blind man staring at the moon.

You can bet my ears pricked up when I read that. Like a hound on point I was. A bit later: “The circle in the centre of this circling poem has become a 'circumambience' prison-wall that imprisons ('immures', 'enthrals').” Be still my heart! "Circle", "circling"!? Could it be? Is this another ring-composition? What about the chiasmatic line 20 (which Adam fingers as consisting of monosyllables): "He seems to gaze at that which seems to gaze on him!" 

I've reset the poem to bring out the ring-form possibility. Give it a read and see what you think.

'Tis a strange place, this Limbo!—not a Place,
Yet name it so;—where Time and weary Space
Fettered from flight, with night-mare sense of fleeing,
Strive for their last crepuscular half-being;—
   Lank Space, and scytheless Time with branny hands
   Barren and soundless as the measuring sands,
   Not mark'd by flit of Shades,—unmeaning they
   As moonlight on the dial of the day!
      But that is lovely—looks like Human Time,—
      An Old Man with a steady look sublime,
      That stops his earthly task to watch the skies;
      But he is blind—a Statue hath such eyes;—
         Yet having moonward turn'd his face by chance,
         Gazes the orb with moon-like countenance,
         With scant white hairs, with foretop bald and high,
         He gazes still,—his eyeless face all eye;—
      As 'twere an organ full of silent sight,
      His whole face seemeth to rejoice in light!
      Lip touching lip, all moveless, bust and limb—
      He seems to gaze at that which seems to gaze on him!
   No such sweet sights doth Limbo den immure,
   Wall'd round, and made a spirit-jail secure,
   By the mere horror of blank Naught-at-all,
   Whose circumambience doth these ghosts enthral.
A lurid thought is growthless, dull Privation,
Yet that is but a Purgatory curse;
Hell knows a fear far worse,
A fear—a future state;—'tis positive Negation!

Alternatively:

'Tis a strange place, this Limbo!—not a Place,
Yet name it so;—where Time and weary Space
Fettered from flight, with night-mare sense of fleeing,
Strive for their last crepuscular half-being;—

Lank Space, and scytheless Time with branny hands
Barren and soundless as the measuring sands,
Not mark'd by flit of Shades,—unmeaning they
As moonlight on the dial of the day!

But that is lovely—looks like Human Time,—
An Old Man with a steady look sublime,
That stops his earthly task to watch the skies;
But he is blind—a Statue hath such eyes;—

Yet having moonward turn'd his face by chance,
Gazes the orb with moon-like countenance,
With scant white hairs, with foretop bald and high,
He gazes still,—his eyeless face all eye;—

As 'twere an organ full of silent sight,
His whole face seemeth to rejoice in light!
Lip touching lip, all moveless, bust and limb—
He seems to gaze at that which seems to gaze on him!

No such sweet sights doth Limbo den immure,
Wall'd round, and made a spirit-jail secure,
By the mere horror of blank Naught-at-all,
Whose circumambience doth these ghosts enthral.

A lurid thought is growthless, dull Privation,
Yet that is but a Purgatory curse;
Hell knows a fear far worse,
A fear—a future state;—'tis positive Negation!

The first setting implies a nested structure:

       ( 1 ( 2 (3 ( X ) 3 ) 2 ) 1 )

The second implies a travel structure:

       1 > 2 > 3 > X > 3 > 2 > 1

This, obviously, requires some explanation. But not now.