It’s hard not to see Masdar City as one of the lessons that came out of the mid-aughts dream of the new Gulf. The project, which broke ground in 2008 under the oversight of architecture firm Foster + Partners, was slated to be a two-and-a-half-square-mile, carbon-neutral smart city in Abu Dhabi—a vast experiment in which buildings and infrastructure would be seamlessly integrated, with residents zipping around in driverless electric pods. If all had gone according to plan, Masdar would have been more or less finished by now. But in the wake of the global financial crisis, Foster + Partners ceded control of the plan to the state-backed firm Mubadala, and the completion date was pushed closer to 2025. Today, about 5 percent of the development is built, and the goal of carbon neutrality has been eased to 50 percent.Masdar’s piecemeal growth brings it closer to that of a real city: a slow, sometimes awkward evolution. The question now, says Gerard Evenden, senior executive partner at Foster + Partners, isn’t how to create brand-new cities from the ground up, but how to boldly rethink existing environments.