Different wing sections move with different sine wave functions. Spacebar removes balls. Try adjusting the sine wave phase difference between inner and outer wing movements (about -80 seems to work best to me, visualized with green and red dots).
Half wing sections point at different sprites moving with sine function. The outer wing part follows a different sine phase than the inner wing (outer wing keeps moving when outer slows down and slows when outer wing part speeds). A phase difference of -80 (slider) seems best. You can see the phase difference in the relative motion of green and red dots. There's software like Blender that does this much better, but the mechanisms are largely hidden. So here I'm trying to model the basics.
