Idiosyncratic paragraphs Text-only paragraphs differ from one another only in their words. All the words are typographically the same – typeface, spacings, line-lengths piled up into long deep columns. Systematic regularity of text paragraphs is universally inconvenient for readers, who are unable to find and read once against a specific string of words in previously-read paragraphs. All readers have encountered this problem in essays, articles, novels, news reports. Idiosyncratic paragraphs assist memory and retrieval by readers, by uniquely activating the relevant neural substrates for retaining visual memories. Nearly every paragraph in this book is deliberately unique. Edward Tufte, Seeing With Fresh Eyes variation
The problem with trees Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as: HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS only to find a reference to another leaf: Please see HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww