This is a beautiful quilt!! But have to ask why do you put the cubes in or is that considered part of an OBW?
To answer the question why the cubes? I had it on my design wall for months arranging and rearranging the blocks. I couldn't get them right for some reason. So, I thought let me try a few cubes. WaaLa it worked for me! When I look at my quilt I see a big picture window under the ocean..watching the currents and swirls of the waters...that calm beautiful flow.....and possiably a few hidden treasures in there too : ) Can you see it too?