mike-wsm
It was Boeing, after a visit to Bristols, who had the bright idea of making the wing flex along its length whilst importantly maintaining its torsional rigidity, mostly, but allowing the big forward masses, aka engines, to twist the wing for gust alleviation
I didn't know the engine pods were used to twist the wing leading-edge down in responses to gusts. I just thought the engines weighed the wings down so they wouldn't flex up as much.