This example visualizes the module system from Chapter 10 of Eloquent JavaScript, showing the road network between village locations as a graph. The visualization uses d3.v5 to render an SVG canvas with nodes and edges based on the `roads` array, which defines connections between named places. The code demonstrates modular programming by splitting functionality into separate files, including a `graph` module that exports a `buildGraph` function. It processes road pairs using string splitting and passes them to construct the final `roadGraph` object, highlighting how modular design organizes the data flow.