The flanged cushion is also a change from the standard knife-edge cushion. A flange is a piece of fabric that extends beyond the seam, giving the cushion a gentle, fluttery effect.
Flanged cushion covers can be made with the same fabric as the cover itself (called a self-border) or as an integrated border with a contrasting fabric. These striped pillows sitting on the chairs have the flange on the vertical, rather than all sides. Using the same fabric but turning the pattern a different way includes both ideas and gives you a stunning result.