It is usually a designers thought in many art mediums, to pull from your center on a boarder. What ever your color(s) is in the center, pull(choose) from that to make your border. The reason being is it causes your subject to become pleasing to the eye. More of a calming of colors and a union too. With quilts we can continue to make color from many 'centers'..:0)When in doubt, pull from the center. I really like how you gave examples of different colors for all to see and it is very interesting all the suggestions. Does show the creativity in this group and great imaginations to create with!:))Skeat