The first step was to capture the square charm in a bead basket. After that I did the spirals ~ I do have a thing for spirals. The rest just came about intuitively. There were times in the process when I didn't like it much, but fortunately it all worked out in the end and I'm happy with the end result. The circle is the size of a CD (I traced one onto the Fast 2 Fuse that I used as my stabilizer) so it's just over 4 1/2 inches across.
Close up shows details of mica 'donuts' below the bead
stacks in the bottom left.