Interested patrons appreciate Mr. Heatherwick’s ability to solve problems while focusing, as he put it, on “what it takes to make it happen.” Intrinsic to his design for the Garden Bridge are quintessentially British qualities, intended to ease public approval and open philanthropists’ wallets. A relaxed promenade among greenery frames river and city views. The bridge would bring fragrant flowers and birdsong into the hard, noisy heart of London. A steel-and-concrete-composite core strengthened by a copper-nickel sheath built like a ship’s hull make possible the tapering piers and delicately thin deck visible in models at the Cooper Hewitt.