This interactive tool lets users create and edit directed graphs by dragging nodes, clicking to add new ones, and selecting edges. It visualizes a force-directed layout using `d3.forceSimulation` with custom link and node elements. The code handles node dragging, edge creation between nodes, and node deletion, with reflexive edges drawn as loops. Styling distinguishes selected links with dashed strokes, while the simulation uses `d3.drag` and `d3.forceLink` to manage interactions and positions.