A Pattern Language A Book by Christopher Alexander, Murray Silverstein & Sara Ishikawa www.goodreads.com Its place in the web of nature9. Scattered Work21. Four-Story Limit51. Green Streets53. Main Gateways+27 More Deliberate actspatternsof.design125 Best Architecture BooksThe Timeless Way of BuildingThe design systems between usCollaborative Information Architecture at Scale architectureurbanismlifeconstruction
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