This interactive collapsible tree displays hierarchical organizational data with expandable and collapsible nodes, shown as circles with labels connected by curved paths. The visualization uses D3.js v4’s tree layout and hierarchy API to position nodes, while user clicks toggle children visibility and trigger smooth 750ms transitions. Data is defined in a JavaScript object with department and role structure, rendered as SVG elements with animated enter, update, and exit states. Node styling distinguishes collapsible parent nodes with filled circles.