There's probably a thread on this one in the development section, but I haven't had time to check.
It's the proposed MOMA tower in New York city.
I absolutely love it, possibly one of the best proposals for a modern tower I've seen. When I first saw the plans I immediately thought of an unbuilt constructivist tower designed by two Russian architects 90 years ago. Can't remember the name. But this one adds to that a uniquely modern element through the ingenious use of space enabled by numerous cross beams.
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all images from www.archiportale.com where they can be greatly enlarged