“It sounds, at first blush, like an oversize architectural joke — a skyscraper where each floor would revolve independently around a central core, not only making a 360-degree rotation but also creating a constantly shifting profile.” But architect David Fisher isn’t joking, and his vision for a spinning skyscraper is on the way to becoming reality in the wealthy Arab metropolis of Dubai. This week, Fisher has been attempting to sell Chicago officials on the idea of a similar structure in America’s Second City.