This example displays a network of mouse breeding colonies through a force-directed layout. It shows how individual animals, represented as nodes, connect through parent–offspring relationships, with node color indicating animal role and node size reflecting degree centrality. The visualization uses D3 v4's forceSimulation API to run a physics-based layout, with multiple forces such as "charge" for repulsion and "link" for attraction between connected nodes. Links are rendered as SVG lines with arrow markers, while the underlying data comes from CSV files specifying the mouse pedigrees. A button allows the user to resize nodes by their calculated degree centrality.