I learned a fast way to do pinwheels. You put two squares right sides together and sew a quarter inch all around the perimeter. Then you cut it in half on the diagonal and you get 2 half squares that you can turn and sew into a pinwheel. Look for the seam where the point is cut and pin at that point. Seems to be a good guide for me. That might not be really clear but I will try to find the link to the youtube video.