One World Trade Center built with "Steel Slats"
http://gothamist.com/2012/05/26/1_world_trade_centers_base_to_have.php
"The previous prismatic panels caused worries that they were easily break and the project was stopped after $10 million had been spent. Now, the new panels—which Cuozzo describes as "vertical glass fins protruding from panels of stainless steel slats. The fins will be arrayed in patterns that will vary as they move up the facade"—are expected to cost $40 million."