Lots of applique.
Cut four 3 1/2" squares out of background fabric.
Cut four 3 1/2" squares out of main fabric.
Using these squares make two identical pinwheel blocks following the instructions in block B-2.
Cut or print the block diagram onto freezer paper. Carefully cut out the center circle without cutting apart the rest of the block.
Iron the freezer paper circle onto the right side of one of the pinwheel blocks making sure to center it. Cut away the center of the other pinwheel block to reduce the bulk.
Layer the sections as in the photo and baste through all the layers. Remember to stay far enough away from the edge to allow for the seam allowance to be turned under. Notice that the top section has been rotated 45 degrees.
Applique the circle onto the bottom pinwheel. Cut away some of the bulk on the back. Trim this block to 5"x5".
I tried to see the detail in Jane's block but couldn't quite figure out how she did her white border. I decided to go for the middle route between a solid border and a block made out of half square triangles.
Out of background fabric cut 4 squares 3"x3". Sew them together to make a four-patch.
Cut the remaining freezer paper section as in the photo and iron to the four-patch, making sure to line up the seams. Cut out the center section leaving about 1/4" seam allowance. Clip the curves to within a couple of threads from the seam.
Place the "pinwheel section" face up on the table. Place the background section right side up on top of it. Line up the seams carefully. Baste through all the layers. Make sure that you leave enough room for the seams to be turned under.
Reverse applique the background four-patch section to the pinwheel section.
Trim the block to 5". You may wish to trim away some of the bulk from the back of the block at this point.