Selvectonian Nest

Construction

Selvectonian nest are truly sights to behold. Selvectonian, though simplistic in technology and tools, are nothing if not industrious. This is shown in their nest structure, where Selvectonian truly display their intelligence when it comes to construction and engineering. Their nest are towering, stretching both high into the sky and deep below the surface. Dozens of tunnel entrances dot the outside that lead deep into the labyrinthine nest in which all roads interconnect to the several chambers.
Though it might appear like a mess to any other race there is great care to Selvectonian structures. Air vents are the first things to to be constructed, where the hot air and carbon that would normally choke out the race is pushed out by cool air that comes in, and irrigation tunnels are dug out to pre-plan where the water will go so that nothing needs work later. In the beginning it looks much like a skeleton, where key points are reinforced and shaped so to allow the rest of it to be built.
Next would be the chambers. Despite having no eyes or known forms of writing the ability to build a nest is second nature to a Selvectonian, as if it were encoded at birth. Selvectonians know where and why they build a certain chamber and what purpose it will serve. Layers higher up in the nest would be food storage, where there are chutes that allow the quick sending of food, and where the children sometimes have fun and ride in. The middle layer, which would be at ground level is more where the water would be stored, where giant cisterns are made and have basic pumps and water gates made control the flow to the farms below. Only one cistern at a time is filled however, so that if construction and maintenance need to be done they can move it to the secondary or third cistern.
The Third and last layer is deep underground to prevent leakage and also provide protection. Typically these layers also connect to the massive caverns in which they hunt and gather. This layer is the nursery and also the most heavily guarded. Matrons and their young will reside here as well as expecting mothers for the duration of their pregnancies.

Material

Selvectonians construct their nest completely from one material. It is a bio organic mixture of dirt, clay, mud, wood, stone, and their own stomach enzyme. Selvectonians will chew and ingest these materials only to spit it back up an hour later as a piping hot paste in which can be shaped and molded into the desired shape. It may seem painful but surprisingly Selvectonians enjoy the feeling, the inside of their mouth is actually very tough to prevent things like splinters and sharp rocks from cutting them, its more akin to boiled thick leather. Though is sacrifices taste, for them it provides a pleasant feeling that they thoroughly enjoy, only matched by their love of food. They also don't need to worry about their teeth since both the teeth on their mandibles and in their mouth regrow constantly and shed rather commonly throughout their life. They also have a very powerful bit force that allows them to bite and chew through rocks with ease.
Most traders actually prize this material despite its origins because it is extremely sturdy and holds up well during storms. It also last a good while for it not very porous and surprisingly water tight and a very good insulator. Many human and humanoids constructions are made up of the deep amber color, if their not painted over. It has also been recorded to survival cannonballs with little to no issue when applied in a thick enough layer. In many ways Selvectonian nest are neigh impenetrable fortresses that house labyrinths confusing to all but Slevectonians.