A good cubist portrait needs...

I've looked at some cubist portraits. There are a few major factors that determine a good cubist portraits.

Combination of some basic geometric shapes
Multiple plane defined by different colors
Some physics are still applied in the picture (e.g. light projection, shadows)
Some scales/proportions are irregular or exaggerated
Color contrast is relatively clear within the picture
The color combination of the character works well with the background colors