Thanks Linda. I am still not sure about the one on the bottom right - I may redo that one but we will see what Lestrong thinks.
As for a round on Melinda's - what about the one similar to one on the cover of the book by Judy Laquidara (2nd from the left) with the triangles and squares?
If you used an all black background alternating green and yellow for the triangles (green on the outside and yellow toward my round) I think it would pull the center design back in. No need to do the black square since the background would be all black.