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
Pedagogical Sketchbook A Book by Paul Klee Half-winged, half-imprisonedTO STAND DESPITE ALL POSSIBILITIES TO FALLThe senses of form and toneA mind so in flux
Half-winged, half-imprisoned The contrast between man’s ideological capacity to move at random through material and metaphysical spaces and his physical limitations, is the origin of all human tragedy. It is this contrast between power and prostration that implies the duality of human existence. Half winged—half imprisoned, this is man! ideasbody
The senses of form and tone Man painted and danced long before he learned to write and construct. The senses of form and tone are his primordial heritage. Sibyl Moholy-Nagy artformdance
A mind so in flux A mind so in flux, so sensitive to intuitive insights, could never write an academic textbook. All he could retain on paper were indications, hints, allusions, like the delicate color dots and line plays on his pictures. Sibyl Moholy-Nagy drawingmind