Designer, implementor, user, writer A Fragment by Donald Knuth dl.acm.org Thus, I came to the conclusion that the designer of a new system must not only be the implementor and the first large-scale user; the designer should also write the first user manual. The separation of any of these four components would have hurt TeX significantly. If I had not participated fully in all these activities, literally hundreds of improvements would never have been made, because I would never have thought of them or perceived why they were important. Eating your own dog food making
Paths, edges, districts, nodes, landmarks The contents of the city's images which are referable to physical forms can conveniently be classified into five types of elements: paths, edges, districts, nodes, and landmarks. Paths are the channels along which the observer customarily, occasionally, or potentially moved. Edges are the linear elements not used or considered as paths by the observer. They are the boundaries. Districts are the medium-to-large sections of the city, conceived of as having two-dimensional extent. Nodes are points, the strategic spots in a city into which an observer can enter, and which are the intensive foci to and from which they are traveling. Landmarks are another type of point-reference, but in this case the observer does not enter within them, they are external. They are usually a rather simply defined physical object: building, sign, store, or mountain. Kevin Lynch, The Image of the City City districtsAs a kind of gateway cities