Agree with PaperPrincess - I would stablize those pinwheels with outline quilting around the pinwheels. Then I would quilt 2-3 or 4 shallow curved semi-circles starting about 1/4-1/2" out from each of the folded corners of the pinwheel radiating out towards the outside of the block. Stagger them so that they are not parallel to each other so it gives a circular motion. If your first shallow semi-circle starts closest to the pinwheel and a little below the tip of a pinwheel blade, curve it down partway past the folded part of the blade. Then as you move out away from the pinwheel, and that first curve, drop down and start your next shallow curve a little below where you began you first curve. Hard to tell how many curves you would need around each of the blade - it would depend on how far apart you quilt each curve so that you get the motion you need. Easier to do that it is to try a verbally explain the conception. Will be interesting in seeing how you quilt around those pinwheels - don't forget to post a picture. Good luck - someown is sure going to be lucky if they get this as a gift. Have you given it a name yet???