One simple conventional color-wheel in 'white background' in vector style and highly saturated colors. make it a logo style. void circular center you can see through and see the background. pure white rgb (255, 255, 255) background. white border is good. the wheel has a transparend center through which you can see the background. zoom out so the wheel is far and equidistant from the limits of the image. perfect round circle. just one array of colors.