This is a really cute wallhanging and the twister border is clever. I just finished a twister wreath for Christmas and used a double needle outline (echo) on the outside and inside of the pinwheels (it would be on your black border) using red thread and green thread. Maybe you could get a varigated green/orange to use in one needle and a light color in the other needle to echo and perhaps a serpentine stitch in the purple border of panel. Let us know how you finish it.