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
Cool URIs don't change An Essay by Tim Berners-Lee www.w3.org What makes a cool URI? A cool URI is one which does not change. What sorts of URI change? URIs don't change: people change them. The User Interface of URLs www
Irwin Volumes Show image 0 Show image 1 Show image 2 Show image 3 Show image 4 Black Line Volume, String Line-Light Volume, Corridor String Piece, Line Rectangle "The resultant black rectangle was not what you "looked at" – there was actually nothing to focus on – but soon it brought the space into focus with a distinct visual snap. From inside, the light in the area seemed different, more substantial, and the wall color began to shift ambiguously. From outside the area, the tape seemed to lift the plane of the floor upward in your field of vision, and it also made the room seem wider and shallower than it really was." — Roberta Smith Robert Irwin, Robert Irwin: A Conditional Art You are the one that is changed