1. First rendering.
2. Grayscale image derived from first rendering.
3. Second grayscale image derived from first rendering.
4. Likely derived from 2nd grayscale (3) by gradient mapping.
5. Grayscale image derived from 4.
6. Grayscale image derived from 5 by "inverting" the image.
7. Derived from 1 by gradient mapping.
