Amy Purdy's bionic grace on 'Dancing With the Stars'
Like any good dancer, Amy Purdy has a great pair of legs. But as with any good dancer, there is far more to her talent than what she does with them. Still, the legs grab your attention. Purdy is a double amputee, and her prosthetic limbs have carried her with deceptive ease through four weeks of competition on ABC's "Dancing With the Stars." She and partner Derek Hough have been scoring just below such unsurprising f…