Contrast Flange or Welt?
Contrast Flange: a strip of fabric that can be added to the edge of a pillow to increase its size, and can be made from a contrasting fabric to the pillow itself
Constrast Welt: a fabric-covered cord that is sewn into a seam using a different fabric than the main material
Self-Welt: A self welt iswhen the cord is done out of the same fabric.
Knife Edge: A knife edge pillow isone with a seam without a decorative finish. It tapers to sharp, crisp edges and corners, creating a very simple, clean, polished look.