People think of feathers as flat.
Nothing could be further from the truth, I know because I sweep them up daily, cleaning the bird room. Feathers are fascinating series of compound curves and planes.
Below, primary flight feathers are given a menacingly sexy rendering by costume designer Catherine Zuber.
The costume works because it focuses on one aspect of one kind of feather. Everything else is eliminated to really see those long finger-like primary flight feathers. Tears in between the barbules give those knife like shapes more impact.
It's all about the impact. The costume works. What's missing is that each wing's primaries are also curved in opposite directions, right and left. Too complex for the stage, but not for sculpture.
Photo by Sara Krulwich from the New York Times review of The Tempest by the Bridge Project. article, Air sprite, Feral Creature, Rapturous Love and Other Scorcery.