Ok, I had to know how it's done. It reminded me of those cool tables at the children's museums where you can pile up the earth and it changes to mountain/water/land through projection above. But it also reminded me of the book my kid has where light triggers each page to be read. So, after some time spent googling.... "For the printed parts of the pages are supplemented by projected content, thus permitting interactive elements and moments of surprise in the form of animations with sound.... A very special characteristic of iart's interactive books is the fact that the printed and projected contents can hardly be distinguished from one another. The analogue and digital worlds seem to merge on the pages of the book. As a result, the book does not only appear in virtual superposition, but adds to a new experience by offering the possibility of a haptic sensation. In addition, interactive elements and an elaborate sensor technology provide an intuitive access to the contents: animations are triggered when a page is turned or a highlighted area of the image is touched, and the language of the texts can be changed with a simple touch. At the same time, the technology remains in the background: hidden in the ceiling, inside the base of the book, without monitor, mouse, keys and cursor. For the readers, only the book with its physical pages and interactive animations can be seen, touched and heard." --https://iart.ch/en/-/die-interaktiven-bucher-von-iart-ein-framework I found out how! This has both a printed book and a digital aspect!