The architecture of a sukkah is described in sacred Hebrew texts in ways that are not dissimilar to how NYC Zoning and Building Codes regulate construction in the city. Zoning informs one where to build, while the BC will regulate materials, structure and various assemblies. Everything else (in sukkah construction or in NYC buildings) is open to interpretation, as long as the design remains “as of right”.
According to Jewish tradition, the sukkah is a structure meant to acknowledge the power of the Higher Authority and remembrance of nomadic past through temporary foregoing creature comforts by putting oneself into the mercy of the elements. It is also moment of acknowledgment of connection and interface between the mundane and the divine.
The one place where all this occurs on a daily basis is a standard NYC subway entrance. There almost 500 stations and at least a thousand entrances. At least a third of them is exposed to the elements (the ones on the north-west corner of Union Sq are two such examples) and this is where the nomadic population of New Yorkers and tourists ceaselessly pass in great numbers. Just as one emerges from spending the year in the confined space under the one's roof to experience the boundless space of heaven above, a city commuter spends most of their time in a dark confined space, to emerge into the cityscape aboveground. This is where one ought to stop and think about the transition between an abstract diagram of a subway map, the physical city and the eternal realm of the elements. This is where one ought to notice the sky and be reminded of the interface between the natural and the divine.
One may also be mindful of the fact that New York Subway entrances are ideal pre-made sukkah spaces, convertible with very minimal effort (“as of right” by both Hebrew and NYC codes).