From my point of view “Flatlands” represents a perfect description of typography as a form. Because the majority of type as we experience it comes in 2-dimension form. The fifth dimension is explained as something that exists in 3-dimensional space and evolves over time and also is able progress in more then one routines. If we were to transform this into typographic terms we would arrive to a decision that typography in 5-th dimension could be represented as hypertext.
Hypertext fiction is a genre of electronic literature, characterized by the use of hypertext links which provides a new context for non-linearity in “literature” and reader interaction. The reader typically chooses links to move from one node of text to the next, and in this fashion arranges a story from a deeper pool of potential stories. Its spirit can also be seen in interactive fiction.
In print that could be achieve through a use of references that lead the reader to a multiply amount of choices. One of the greatest examples of that would be Vladimir Nabokov;s “Pale Fire”.
Rita Toewes gives an interesting outlook on hypertext fiction in her article LINK