"(…) as we begin to read, a temporal process commences, which in addition to the two dimensions of surface and to the dimension of space—we think of the body of the book!—brings the fourth dimension of time. One of the essential characteristics of time is that the direction in which it moves is irreversible. We can ‘read the first three dimensions in similar fashion in one direction or another; which is not possible for the dimension of time’."
— HOCHULI, Jost & KINROSS, Robin. Designing books: practice and theory. Hyphen Press. London,1996. p.12