National Contiguity visualizes the adjacency relationships between nations as a force-directed network graph. The code uses d3.forceSimulation with link, charge, and center forces to position nodes, while SVG lines and circles represent connections and countries. The network links are loaded from a remote JSON file containing country data. Hovering is not implemented, but the static layout shows the clustering of contiguous nations through explicit link lines, with node coordinates updated on each tick of the simulation.