This example compares node-link diagrams with adjacency matrices for visualizing network data. It displays a force-directed graph using `d3.forceSimulation`, `forceLink`, and `forceManyBody` alongside a corresponding matrix where cell opacity reflects link weights. Clicking a node in the graph or a grid cell in the matrix highlights the matching link in both views using `d3.select` and stroke styling. The data comes from a CSV of Dublin infection network edges, parsed and rendered as SVG rectangles and drag-enabled nodes.