skybrook
As you can see in this photograph, and this one primaries, secondaries and tertiaries are parallel and do not unfurl into one and the same in any respects. There is no row of feathers that only partially overlaps the primaries, and shorter primaries do not fold up on top of the longer ones. You have warmth feathers for the arm, aka tertiaries, and then you have flight feathers: primaries and secondaries.