Master Craftsman Step 6 - Unity

A new record - starting on the final step now, when it's not due till next February. My original intent - and I kept at it for several weeks - was the milky way sky, with Joshua trees in silhouette in front; however I don't think it's a good design to show color unity. After kicking around a few ideas, I finally decided on this one.
My painting teacher should be proud of me; I painted it first.

So far:

Detail of the hill: