From the NY Times:
Casting a glance skyward in Manhattan these days may include the risk of beholding not sky but horizontal appendages that curve and jut outward from the sides of residential towers and hover like geometric mutants above the roofs of vertically challenged neighbors, inhabiting space once occupied by open air.
Typically built of glass and steel and suspended in midair, they are not optical illusions. In fact, they are vista-grabbing, profit-generating cantilevers the likes of which Frank Lloyd Wright probably did not contemplate in 1935 when he designed a rural residence known as Fallingwater, which levitated, with assistance from cantilevers, above a 30-foot waterfall in Mill Run, Pa. Wright cantilevered for the aesthetic thrill of it. Piers and bridges cantilever for the sake of a design imperative. The cantilevered entrance of the former IBM building at 590 Madison Avenue, designed by Edward Larrabee Barnes & Associates, continues to be a piece of modernist eye candy that wows passers-by.
But the escalating popularity of cantilevers in luxury residential (and some commercial) developments is apparently driven by — what else? — economics. With “bigger is better” the prevailing mantra among developers, cantilevers are getting bigger, too: superior apartment layouts are the desired endgame.