I used a circle attachment on my machine and 2 layers of fabric. Stitched 3 different sized circles, then cut out the top fabric to show the bottom fabric. Then I used embroidery thread and fancy stitches to finish the edges of the fabric.
The black blocks are just circles of fancy stitches in the same colours I used for the cut out blocks, at the same size. I marked the sizes with nail polish on the circle attachment so I would get them even each time.
I used the Westalee Circles on Quilts ruler to do the quilting, which you can't really see very well, but the circles start at the junctions of the blocks and go out from there.
To hang it, I am going to brace it in back with dowels, like a kite from corner to corner each side, then put a hanging sleeve across the second coloured row. (That's the plan, anyway.)
Watson