I also thought it might be neat to play with complementary contrast and colour ratio (i.e. 1:3 yellow to purple, etc).
I made two blocks using the Fibonacci sequence up to 13 again and rotated one of them to get this:
Hmm, it has potential, but it needs more and I'm not sure quite what yet. Something to balance the colour ratios? Using the Golden Ratio is not so easy. LOL! Thoughts?