The Radiant City Le Corbusier’s advocacy of what he had come to call the “Radiant City” continued to his death, and in the 1960s he published his most complete vision, drawn with seductive elegance and insanely mesmerizing to the generation of architects teaching in my school days, for whom possession of a Corb drawing or painting was tantamount to owning a relic of the True Cross. Michael Sorkin, 20 Minutes in Manhattan utopia
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