This visualization uses a D3.js force-directed layout to map the Harry Potter universe as a three-level network, with Hogwarts at the root, the houses Gryffindor and Slytherin at the middle level, and characters such as Harry, Hermione, Draco, and Snape at the leaves. The code builds an SVG scene using `d3.forceSimulation` with `forceLink` and `forceManyBody` to position nodes, color-coded by level with `d3.scaleOrdinal`. Nodes are draggable via D3’s drag behavior, and labels are drawn alongside circles to identify each entity.