It has been known for some time that the firm of Chicago architect and MacArthur Genius Grant recipient Jeanne Gang has been planning a residential tower for San Francisco’s Transbay District, south of Market Street. Now Gang and developer Tishman Speyer have revealed renderings of a 400-foot-tall, 40-story building clad in masonry tiles at 160 Folsom Street.

The design shows units with large bay windows, a staple in the Bay Area, but the bays jut out at sharp angles and change configuration up the elevation, lending a twisting profile to the tower. The design is inspired in part by the bay windows of Timothy Pflueger’s 450 Sutter Street building. “What I like about tall buildings is what you do with the height, the incremental moves along the way,” Gang told San Francisco Chronicle critic John King. Studio Gang and Tishman Speyer both told AN that Gang could not comment at this point in the process.

Thanks to a deal with local officials in which the building was granted another hundred feet of height, the development, located about a block from the Embarcadero, will, if approved, contain about 35 percent affordable housing. That is the same figure the overpriced city is hoping to achieve for future developments. Currently all projects in San Francisco are required to set aside about about 12 percent of their units as affordable, or pay a fee. Gang’s building will house 390 condominiums, split between the tower and an eight-story shorter building of 139 units, 75 of which will be designated low-income.

The haggling over height is part of a larger debate over Transbay’s character, as the once sleepy area stands at a crossroads. OMA has proposed a 550-foot tower nearby, and SOM’s transbay tower is also 400 feet tall.

The Transbay District, anchored by Pelli Clarke Pelli’s 1,070-foot Transbay Center, is now set to contain new buildings by Studio Gang, Pelli Clarke Pelli, Renzo Piano—a remarkable conglomeration in an area that just a decade ago was a relative afterthought. Overall the district is set to contain more than six million square feet of new office space, nearly 4,400 new housing units, and about 100,000 square feet of new retail space, according to the Transbay Joint Powers Authority.