I like the top of the picture with the inner green border.
I like how it "floats" the pink blocks.
Audition green inner, white/frog middle, pink outer. Do you have enough pink to also bind it?
For some reason, I prefer the darker colors toward the outside. Maybe my art background, painting, matting, dark frame?
Might be as simple as, the pink will show less soiling than the white, and the outside edges usually get handled more.
dunno.