The Grey has a normal wing with about 8 primary flights, the secondary flights are the feathers that start in the wing near the rump , its got a right angle corner formed in the wing , this is considered normal.
The Green however has long primary flights and long secondary flights , no right angle formed at all the feathers just flow through in one line , Its these secondary flights that start to curve as they get longer and the strength of the feather barb gets weaker, This creates the Shark fin feather , or sails as some call them.