I have a friend who made some thing like this. She cut two equal circles and sewed them together all the way around. For this you would use a white and a print. Clip the edges. After sewing, separate the two fabrics and make a small slit in the print near the edge. Don't cut the white. Turn the circles through the slit and then using a chopstick smooth out the curves. Iron flat. You turn the white sides over to form the square. This looks like it has batting in, but she didn't use any. She actually marked the finished square on the circles and sewed them together in rows which gave her the edges to turn over. If you Google "denim circle quilt" you can find this made with ragged edges.