Troika is...

... a city on a plate on a mountaintop. The city's governors must maintain balance in all things lest it tip and slide down the mountainside. Sensitive to all forms of unbalance, their building laws are a tangled mess, each brick must be examined and weighed, it's manufacture and origin listed. Ethnic diversity is mandatory, a ghetto could doom the entire city. The government takes it upon itself to form and sponsor metaphysically opposing religious groups. For every fire god there will be a sea lord.

... a city of chains, hanging from a distant source. The buildings are chains, the roads are chains, the doors and windows are chains. Everyone feels the draft, privacy is bought with thick hedges of chains. The dispossessed live up the foundational chains, in the huge arches of their links. The further from the goodly citizens of the base the better.

... diffused. A great forest, scattered buildings, unmapped and reliant on local knowledge and word of mouth to traverse. Directions are sought from old men in doorways who instruct you on changing bird song and leaf shape, to follow the sound of water. Sections come and go, swallowed by nature.

... a dungeon. Gigantic, sprawling and dangerous. The city occupies a certain area, but that certain area shifts like a great slug in response to changing environment. As the east becomes dangerous it organically sprawls west, chambers are vacated and occupied, land is ceded to random encounters.

... in the world giant's eye. From their perspective the city covers the walls of an enormous bowl, able to look out past the rim at the activities of the world giant, progenitor of fire and life and many other important things. This vantage point has made Troika a seat of farseers who spend their days watching the unfathomable sights of the world giant trying to divine the past and future from what they see.

... at the end of time. Its edges crumble into stark nothing. A slice of an ancient city populated by the people of the past who use this unique position to double back on themselves through its many doors.

... the eternal city. It changes with the age but is always a city of doors and crossroads, philosophers, doomed to fail.

... the philosopher city. A mecca for thinkers, who flock to it in hope of the chance to demonstrate their ideas. Every corner has a creature on a box shouting its theories, every back room is occupied by a master and his pupils, the government are the most lauded masters competing for a term of philosophic hegemony.

... the city of the universal congress. The mysterious governors pass down obscure edicts, to collect one of every book, to kill all starlings, to not look East for three days, to not step on the cracks. To live in Troika is to live every day like an eccentric parlour game or ritual. Despite their apparent lunacy, the city is prosperous and safe, its edicts effecting beneficial change in the most sideways manner.