Judy asked how the blue background was pieced, and the answer is free hand cutting and sewing. Below, I'll describe the method, and if I have time this week, I'll post some in progress pictures of some other strips being pieced so that you can see how it was done.
Sometimes I roughly cut strips of fabric, then made a wavy cut across the doubled fabric. If one strip was longer than the other, I clipped into the longer one at the top of the shorter one. After removing the extra, overlapping fabric, the strips were flipped right sides together and carefully stitched. The stitching is slower than straight seams, as you need to keep matching up the fabric edges, but I just try to keep gently aligning them as I sew, and stopping when necessary. The seams in this quilt were almost all pressed towards the darker fabric, but if I was to cut deeper curves, I'd press in the direction that the seam wanted to go.
After quite a few strips were together, I laid it out and stood back to see where I needed to add more, or adjust the color. Wherever I wanted to insert another strip, I made a wavy cut. Since there are now two cuts that need another fabric inserted between, the wavy strip was just laid on top of the fabric that I wanted to insert, and I carefully cut along the raw edge to match it. Once that new seam was sewn, the new strip was placed under the remaining wavy cut, and another matching cut was made.