#iterator anatomy

You can see data moving through individual strands within coral neurons

We've known since the beginning that iterators are (massive) purposed organisms, which are described to us as being more often than not "meat tubes in metal boxes"

Another good parallel to what iterators are would be cabinet beasts, brainmass in a box, which were said by the devs to be a good clue on how FP got the rot (and with watcher we finally get to see just how cerebral rot can get)

Downpour attempted to display this "guts in a metal box" aspect of iterators with The Rot in rivulet's campaign, although because of how development went, they had to reuse plant assets from farm arrays and sky islands instead of making custom meaty assets (they also used cabinet beasts for this)

damn we back on the rain world train this week

I think the iterator puppets should be treated more like “puppets” - they act like faces and names for otherwise incomprehensibly large beings. When the slugcat listens to Five Pebbles speak, they are being catalogued, analyzed, and archived by a relatively minor and to my knowledge unnecessary part of a greater whole (since the world of RW is so odd and even has its own laws of physics (that’s another post I don’t feel qualified to make yet), it’s possible that iterators have personalities as a byproduct of creating such a large biological computer system). 

I would also like to think that, unless they are simply a byproduct of their size, the iterator puppets and personalities were created by the Benefactors/Ancients/Creators/Whatever You Call Those Guys to carry some symbolic weight, to make it feel like another person was going through the all-important struggle to reach ascension so they could rest in their luxurious cities without fear of treading too far over the lines of their beliefs.

I believe this is why the iterators have faces and not faceless masks - to symbolize their sacrifice, taking the ABCs’ place in the cycle so the ABCs could feel more distant from it. An iterator was a surrogate person, a necessary sacrifice to separate the ABCs (both symbolically and literally) from the physical world they detested so much

they might as well be the closest extant cousin of iterators

a photoplasmic brain with a steam producing body/nest, the similarities to overseers (and even neurons to an extent) is undeniable

(thank you @iteratorsex for the overseer gif, all other gifs in this post are from the wiki)

you can see them gathering resources (dust (for food? definetively for growing the boxworm) and potentially water or at least hydrogen and oxygen) like a jellyfish or perhaps a sponge (the way it opens and closes its mouth is very cute too)

Here we have a schematic for a refuse reclamation automaton. It's an early design, but the long tubular body and single eye-mouth are quite similar to the later models.

mmm, interesting

btw the way the tendrils unfurl into conveyor fans here remind me of a theory ive had that overseers deploy a thin membrane in order to project holograms to

the boxworm is a body actioned through pneumatics and also a host for the eggs to grow in

the activation animation is very fun (are those glass windows in the box "eyes"?)

is the water gathered by the fire sprite? or is it created by combining hydrogen and oxygen? if the latter, would these gasses be collected or synthesized through organic processes? either way it serves the same function as hemolymph in spider legs, even if the shape is worm-like

soft robotics comes to mind (here's another example)

talking about the eggs, i wonder what's the lifecycle like? do the fire sprites grow their own boxworm from zero? slowly from gathered dust? or is this an intestinal worm situation, and each boxworm segment eventually separates once its corresponding fire sprite matures?

now, the structure of the boxworm and the fire sprite larva situation has made me realize a possibility that would have me reconsider and in a way complete my iterator biota lifecycle theory:

coral stems are segmented with little balls/openings, kinda like the boxworm in a way

while coral stems are bundles of mycelia and a number of small flashing cores sheathed on self-grown shells, it is possible neuronflies and overseers are grown from these flashing dots

Given the similarities to axon terminals I was wondering if they were for delivering information/status report of their surrounding equipment

But the one at moon's gravity disruptor feels more like its sampling data from the engine (the last few times I went through that room it ragdolled very hard upon entering due to the gravity lol)

And looking at that screenshot I just took from the map website, it also has the "reading halo", so it probably is catching on information rather than relaying it

Ah, these things - there's not a lot to go on with them, but they're certainly interesting. I'm going to use the game's internal nomenclature and call them "coral stems" for clarity.

Coral stems seem to interact with an Iterator's internal biota in much the same way as their more common cousin, the wall mycelia. Both organisms sprout from the Iterator's internal walls, attracting to their hyphae neuron flies and the free-floating hyphae of coral neurons and inspectors. The sparking effect produced upon contact with these organisms is identical to that seen between interacting overseers, so I'm inclined to believe it represents the exchange of information (rather than say, energy or nutrients) between an Iterator's stationary machinery and its free-floating organic parts. The question then is how the role of coral stems in this interface differs from the role of the wall mycelia.

As you implied, the segmented body of a coral stem closely resembles an axon wrapped in a myelin sheath, the part of a neuron that transmits signals away from the cell body. In such an analogy, the cell body would have to be the machinery the coral stem is anchored to. The wispy mycelia growing from that machinery would then seem to fit the description of dendritic branches, thin growths that receive signals from other cells. So one interpretation could be that the coral stems and wall mycelia perform opposite functions, delivering messages to and receiving messages from the free-floating biota respectively.

Another possibility is that the wall mycelia and coral stems are both sensory organs, but with complementary roles. The mats of wall mycelia are not especially dense, but their hyphae extend into a large part of an Iterator's internal spaces. This makes them well-adapted to sensing macroscopic organisms like neuron flies or coral neurons. These organisms are unevenly distributed in a way that requires hyphae to be able to reach them no matter where they are in a room, but their large size and weight ensures that any nearby hyphae will certainly be disturbed by their presence and brushed against them. In contrast, small particles like microorganisms or chemical traces in the air would be unlikely to collide with the scarce hyphae of wall mycelia, and too light to be reliably detected when they do.

The bundled hyphae of coral stems could act like scent traps for these particles—when one happens to wander into a coral stem's bristles, it's likely to become trapped and bounce around among the dense hyphae for a time, the repeated collisions ensuring that there are many chances for it to be detected. Of course, coral stems are distributed much more sparsely than wall mycelia, but that would be just fine for this purpose. Diffusion ensures that the distribution of small, light particles is relatively homogeneous throughout a space: the air in one part of a room is about the same as the air in any other part, so there'd be no need for too many coral stems close together.

On that note, have you noticed how pieces of the conflux cells are mounted over poles, as if the poles are a grid-rail of sorts?

Well, that's because they most likely are exactly that

Notice how the first step in the closing of a karma gate is a rapid deployment of poles to act as rails for the segments of the first barrier layer

Even puppet chambers aren't just segmented by projection tiles, but also by a grid made out of these rails (most likely for the arm to slide through)