Santiago Calatrava has substantially altered his proposal for a spiraling, 2,000-foot Chicago skyscraper. “With the needle-thin broadcast antenna gone and its airspace replaced by sellable condo space, this is practically a whole new building,” Blair Kamin writes. “At root, the question about the revised plan (which now stands at 160 stories rather than the 150 the developer announced last week) is this: Has Calatrava turned new functional and financial requirements to his advantage — or has he sold out the integrity of the original design?”