1. You must download and install GraphViz from http://www.graphviz.org for your platform (Win32, Unix, Linux, or Mac OS should be supported). The binaries (e.g. dot, fdp, neato, twopi, dot2gxl) should be in your environment path as well.2. On the Unix or Mac platform you need to have the OSProcess and CommandShell Squeak packages installed as well. OSProcess is only known to work in Ian's Unix VM for Mac OS. The predominant Mac VM by John M. McIntosh probably doesn't work with this package yet (get Ian's VM at http://www-sor.inria.fr/~piumarta/squeak/).3. If you want to update your graph model with the node coordinates from running GraphViz then you must install the YAXO Squeak package as well so that #doLayout on a GraphViz object will work. This is purely an add-on right now so if you don't have YAXO, no biggie -- just don't call #doLayout. Graph visualization is a way of representing structural information asdiagrams of abstract graphs and networks. Automatic graph drawing hasmany important applications in software engineering, database and webdesign, networking, and in visual interfaces for many other domains. The Graphviz layout programs take descriptions of graphs in a simpletext language, and make diagrams in several useful formats such asimages and SVG for web pages, Postscript for inclusion in PDF or otherdocuments; or display in an interactive graph browser. (Graphviz alsosupports GXL, an XML dialect.) Graphviz has many useful features for concrete diagrams, such asoptions for colors, fonts, tabular node layouts, line styles,hyperlinks, and custom shapes. In practice, graphs are usually generated from an external datasources, but they can also be created and edited manually, either asraw text files or within a graphical editor. (Graphviz was notintended to be a Visio replacement, so it is probably frustrating totry to use it that way.) So basically, the Squeak interface provided here makes it fairlystraightforward to generate the "dot" language file th