The alley twists and winds for considerable length, doubling back and at one point running across a rickety bridge over itself, all without changing apparent elevation. It crosses several other streets in the process, either as a bridge or as a tunnel; the only street it intersects with is Tasloi, though it does that twice. It is lit dimly at irregular intervals, and seems never far from rain, no matter the weather in the rest of the city. Its perimeter of ancient, two- and three-story stone buildings loom ominously in the dark, and too many never show a light in their windows.
An artists' colony has taken residence along a stretch of Estrigan near Tasloi, laying claim to many of its untenanted warehouses and other abandoned spaces. These have been given over to studios, galleries, and environmental art installations. The artists explore a variety of outre art forms, including psychodioramas, radical body mods, and altered cognition performance pieces— also more conventional work, such as autonomous parasapient holographic sprites, self-modifying swarm displays, and Riemannian architecture.
The artists have done what they can to keep out Strangewarp's perpetual gloom, hanging strings of biolumenescent lanterns across and along the way in their area; although there are gaps where a lantern has crawled away of its own accord and not yet been replaced. Windows dance with holographic displays, and some artists work in open studios or even public spaces, weaving the otherworldly and the macabre in public view. Etrigan alley has few remaining residents who do not share their aesthetic.
At the heart of the colony is a building-size art installation, Theodosophe's Folly, which has become its unofficial community center— and a source of disturbed sleep and nameless dread for many nearby residents. Constructed of a slate-gray material with the texture of granite but the frangibility of drywall, The Folly has been growing for several years and now rises nearly five stories into the air. It has has begun to crawl across several adjacent structures, and has formed an unwelcome skybridge to the building across the way. It branches in a profusion of windowless crawlspace-sized projections, which dont so much terminate as fade away into nonexistence in a manner that eludes close examination. The Folly doesn't grow visibly, but changes suddenly while it is unobserved, often several times a day, always becoming slightly larger.
The Folly's ground floor has the typical features of a building interior, but starting with the second floor its floor plan and design features begin to warp and permute in troubling ways, before branching as crazily as the exterior. It is possible, although not easy, to climb inside a crawlspace and explore it to its terminus. Most turn back, whether out of fear or good judgment, often after having travelled much further than the exterior should allow. Some others report having successfully used a particular branch of the Folly to travel to another warp. The remainder are never heard from again.
The Folly is the work of Theodosophe, an avante garde artist in spatial anomalies. Xe created or modified several other structures in the alley before undertaking what would come to be known as xyr Folly. Shortly after finishing xyr masterpiece, xe retired from spatial anomalies, and launched a long-term performance piece in artificial irreversible neurological decline. Xe has reached the intelligence of a 3 month old, and is in no position to comment on xyr Folly, where its branches lead, whether it will ever stop growing, or whether the sinister intelligence that seems to radiate from it is just our imagination. However, xe always waves xyr hands and coos appreciatively when xyr caretaker takes xem by the Folly in xyr stroller.
The ground floor is more or less stable, within the norm for spatial drift for a Strangewarp locale. A countertop which had abutted a wall might one day have a gap, or a cupboard might turn out to be bigger on the inside than the outside today— perhaps by several hundred feet. For want of other tenants, it has become home to regular gatherings among the local artists, including poetry slams, live music, gallery shows, artificial lifeform exhibitions, obelisk rites, and potlucks. One wing serves as a open gallery for local works, and there is a volunteer-run cafe some evenings. A warm, supportive community has formed around the Folly, of creatures who protect each other from the horrors of the warp— including what they create themselves.