A part of Google’s Material Design description is quite creepy:
“The material is grounded in tactile reality, inspired by the study of paper and ink, yet technologically advanced and open to imagination and magic”
This quote has nothing to do with interface design or programming. Technology does not mean programming. Taking it far away from tech, it is a deep line of conduct.
The material has connection with the physical. It denotes the physical which can be perceived by the sense of touch. Well, the material is what is perceived by senses but more importantly, that can be concretely touched.
Ink and paper has been around for thousands of years. Something written on ink and paper can be a piece of paper, a page or many pages, called a book. If it’s inspired by books, we wonder which ones?