(A)

Another Sanborn sculpture - the Indian Run (1995) text translated from Onondaga to English has four paras, and the fourth para leads in "several directions" like the Sanborn K4 quote.

… the final passage (K4) will lead in several directions. The word directions is - I use intentionally. And that's it. I mean, what can I - if I say any more, I, you know, perhaps give away too much.  (Sanborn 2010)

The second and third "Indian Run" paras are repeated on "Lingua" (2002). All post-K4.

This is probably better writing than K4, since K1 and K2 sounded hokey to me … perhaps he should have had John Le Carre write the K4 plaintext :-)

Para 4:

Now we will light a fire whose smoke will rise, the beautiful smoke piercing the sky.

Moreover, we will plant ourselves a tree we shall call our great tree.

It will put forth roots.

It will grow four roots one of which will go towards the east, the second towards the west, the third root will go towards the south, and the fourth towards the north.

Now there is a single house and a single family, we having united, and this we shall call our league.

We have completed our house, and we call it our longhouse.

We will keep coming here, to the place of the league, the place of the principal the great fire, where smoke will be rising, piercing the sky.

(B)

The Jim Melichar hypothesis - Sanborn has invented a "one-off" encryption system with likely no regard to how difficult he made it.

This is closely related to "the whole plaintext could be released and we still may not know how Sanborn did it" hypothesis; we can call it the "Artichoke-Ozymandias theory" which Bill Briere brought up at the Scheidt meeting in 2015 (all on YouTube).

With more and more plaintext released and nobody solving it, the posterior probability of the JM and AO hypotheses gets closer and closer to one.
(Bayes' theorem)

The competing hypothesis is that there is an aesthetically pleasing, satisfactory solution and the K4 encryption method was derivable from observations about the K4 CT.
>From my point of view - this means the width 7 and width 21 patterns in the K4 CT.
The posterior probability of this alternative hypothesis is getting closer to zero, with so many people having looked at it.

Remember the "Masquerade" story and the ending? I just have a feeling that this isn't going to end well.

["Quest for the Golden Hare" pp 2-3 ... Bamber Gascoigne was the only other person in the world who knew how the puzzle worked and where the hare was buried]

Letters to me were invariably a last resort. Some came from bystanders, desperate because members of their family had changed before their eyes into unapproachable fanatics or were spending the housekeeping money on apparently insane journeys in quest of the treasure. Others were from the Masqueraders themselves, begging for a single word of encouragement to show that they were at least on the right track. I invariably wrote back saying that in my view the puzzle was far too difficult and advising them to give it up.

...

Kit had explained to me the basis of his puzzle, but even with that privileged information I was unable to make it work out. The cause of my growing uneasiness was the thought that if it was in fact impossibly difficult, then I was the only person in the world in a position to form that opinion. Kit considered it very possible, even perhaps dangerously easy, because he had invented it. The publishers considered it possible because Kit had told them it was. But if my hunch was right, and if people all over the world were beating out their brains and emptying their pockets in pursuit of the unattainable, what should I do? Insert a notice in The Times to the effect that Masquerade was insoluble? I would not have been popular in 30 Bedford Square [home of Jonathan Cape]. Yet clearly the one passenger who believes that a train is hurtling off the rails has an obligation sooner or later to pull the communication cord. So it was pleasant indeed when, in spite of my forebodings, the train pulled neatly into the station.

(C)

People are just not so interested in this anymore ...

I submitted the NYT Twitter confirmation of EAST NORTH EAST as a link on Hacker News. On a Sunday evening California time, nobody's upvoted - nobody even cares. And the tech bro readers and potential upvoters of HN should be 
a key part of JS's target audience.

Because ...

(a) Wisdom of crowds! Perhaps collectively people sense the JM hypothesis is true, even if they can't put their finger on it exactly why.
(b) Diminishing returns from each revelation - Sanborn has sensed this. Thanks Sukhwant Singh for sharing.   ...

(D)

There’s five different stories on how long it was supposed to last, two different stories on whether or not Scheidt knew the plain text, and four different stories on how many people did the metal cutting. It’s like Rashomon! I guess this way people keep talking about it for longer.

(1) Sanborn: I thought it would be solved immediately

Surely, someone would crack the code in just a couple of weeks. — Sanborn 2020
I assumed that people would figure it out in a matter of weeks — Sanborn 2009
I really expected [Kryptos] to get decoded in the first few months — Sanborn 2005

(2) Scheidt: It was intended to last 5, 7, or 10 years

Its intent was to last roughly five years; it was modeled along those lines — Scheidt 2000
the last part, perhaps ten — Scheidt 1999
Scheidt figured the whole puzzle would be solved in less than seven years — Scheidt 2009
(five, seven & ten years again) — Scheidt 2006/07

(3) Sanborn: It was intended to last 100 years (at this point you start to worry about his thought process – if one way or another he’s “accidentally” made it impossible)

So anyway that will go on hopefully for a century, long after my death. — Sanborn 2009
I wanted this piece to last into or through the 21st century. — Sanborn 2009

(4) Sanborn: It will/might never be solved

[Kryptos] is so hard to break that the CIA “will never figure it out” — Sanborn 1997
Parts can be deciphered in a matter of weeks or months, but other parts might never be deciphered without the knowledge that Webster has. — Sanborn 1991
Part of it was designed to be deciphered within a couple of weeks. Part of it was designed to be deciphered within a couple of months. And part of it within years, or never. — Sanborn 1991

(5) Sanborn: I’ll decide how long it will take

Like Kryptos, the other public works are designed to exude their information slowly. … For the past 30 years, my task as an artist has been to release this hidden information at a rate commensurate with its importance, and at the time of my choosing so as to prolong the experience of discovery. As we all know, artwork that gives up its form or content quickly is soon forgotten. — Sanborn 2012

—————

(1) Scheidt: I don’t know what the plaintext is

Jim is really the only person that knows what [the sculpture] says. I don’t. And all I
talked about, or we discussed, was the codes themselves, and the limitations as well as
how it could it be adapted into his design. — Scheidt 1991

(2) Scheidt: I checked the first three parts, but not the last part

Q: So the text that’s on the sculpture at some point you went in and you looked at the ciphers
and you worked backwards to the plaintext?
A: Yeah, except for K4 I didn’t. I did all the others. — Scheidt 2015

——————

(1) Sanborn: I did all the metal cutting myself (ok, he probably didn’t mean it literally, but usually people talk the other way around – they use the royal “we” when they mean just themselves)

I cut with jigsaws, by hand, almost 2,000 letters — Sanborn 2020.

(2) An assistant: all the metal cutting was the work of two people

I helped Jim Sanborn build and install a sculpture called Kryptos. Actually another person and I did all the work, but what can ya say? — Oct 2001

I worked at the CIA for about a year… actually, I worked for an artist who had a commission to install a sculpture called “kryptos” at the CIA. I cut all those letters out by hand with a bosch saber saw..well, me and one other person. — May 2001

(3) Sanborn: There were about 20 assistants

Nine hundred jigsaw blades, nine jigsaws, and about 20 assistants because they could not take it; they could only—each assistant lasted, most of the assistants lasted only a week or two. — Sanborn 2009

(4) Sanborn: there were 24 assistants (2013)

So when I made that Kryptos piece, we didn't have water jet cutting. We didn't have robotic water jet cutting. So this was all cut with, with 24 assistants, nine Bosch jigsaws, 900 saw blades in two and a half years of cutting is what it took to cut out Kryptos.