There's a great book called 'Quilting Makes the Quilt' by Lee Cleland, in which the author shows a variety of quilts, with about five of each type quilted in different ways. There's a fan quilt among them. It's a wonderful resource for comparing the different effects of different quilting choices. The book was available from my public library, and it was also available used on Amazon at low cost. She stitched the fan blades in the ditch; she put a diagonal grid on the background of one, did the background of another in a complex pattern of lines and squares, did the third using straight lines fanning out from the bottom point of the fan, bisecting each fan blade and filling the box, did a fourth by quilting a flower in the empty corner, and the last one with an overall meander, including the fan. I thought the first three looked beautiful and the last was the least effective.