I like #4 best if you want to incorporate some blue,
but I do have a suggestion - try switching the placement
of the blue and the green. In other words, try a green
sashing around the blocks, with blue in the little space
you now have green. Also, make the green more of
an olive and the blue not quite so bright and see how
you like that - just my thoughts.
If you used no blue, I do like #1 best.
Marcia