They look kind of thin, so maybe they don't have any batting inside and are just two layers of fabric.
Or maybe have a light fusible backing anyway...
If you notice, the first three all have the same strip sets.....with the second egg pattern turned upside down.
So I bet they just sewed the strips together, cut out the shape, and attached two with like sides together, leaving an opening for turning. Turned, then caught the opening with the double stitched border.