Ethics, Domains, and Principles are each on separate layers so can be printed out and then rotated individually and used as a teaching tool / for exploration by students to match different Principles, to different combinations of Ethics & Domains, and think of applications of these combinations.
The permaculture flower is an image that represents the seven domains of permaculture action. Sometimes, as in the image here, it also incorporates the three permaculture ethics.
Natural earthen finishes are just more tactile. I want to touch them, press my hand against them and feel the texture, warmth or coolness. There is a natural moisture when I press my hand against rammed earth, or a clay plaster.