This is kind of subtle. But I worked out this element of the piece.
I pulled the "trashed" piece out and chose a couple "decorative" stitches to play with. I hate the loop-de-loop stitching in this design, but the rest is done with a kind of honeycomb pattern that I really liked. A color to match each section with the stitching flowing along the shapes of each piece. Where the shapes overlap, the stitching overlaps, too. So the thread colors blend to reinforce the colors.
This is way too subtle close up.
Here are orange and blue threads starting to overlap... on the big picture this creates a subtle green.