These figures are BIG. Each panel is about eight by four.
To create a three dimensional feeling, the contours of the figure are defined with a darker value tile, and the elements are smaller. The elements get larger as they work to the center of the figure, as we would expect to see in the visual field.
At this point, my idea for grout color is dark. Having left large boundary lines, as large as possible within the context of what the grout will cover, the figure will be bound by dark maybe chocolate brown lines.
- Thoughts About Grout (leemalerich.wordpress.com)