by Jason - Color theory, "Four primary colors? Yes, why not? It’s the closest thing to the actual physiology without getting complex." (some pertinent info here http://news.ycombinator.com/item?id=2166494)
Biomimicry & Taxonomy. "Nature's elegant solutions to building challenges include the Scots pine's adaptive growth, the thorny devil's passive water collection, and a leaf's on-site energy production. AskNature can help you solve your design challenges. "