If you've mastered the Buttonhole Scallop, you might want to try this variation. It's a bit more difficult, but a very impressive way of binding an edge.

First, mark two scallops (step 1). The two rows of scallops should touch at the tips, as shown in the drawing. Next, fill the space between the two rows of scallops with the Basting Stitch (step 2). In this drawing, the basting thread is shown in a different color for clarity, but in reality, use the same thread as you use for the Buttonhole Stitches. If you want to, you can pad the scallop even more in the same way as you would pad the Satin Stitch. Work Buttonhole Stitches around the basting thread (step 3). Unlike regular Buttonhole Scallops, the stitches are all parallel (the long part of the stitch is always vertical). The final step involves carefully cutting the fabric away, close to the stitching (step 4).