A D3 v5 tree diagram visualizes overlapping parent-child relationships between US government and economic concepts, where multiple root nodes share common children. The layout uses a horizontal tree with custom x-y positioning after deduplicating nodes by ID, resolving shared descendants. Links are drawn with `d3.linkHorizontal`, and nodes are interactive text elements. The visualization includes zoom/pan support via `d3.zoom`, and animated transitions reposition nodes on update, with a steel-blue highlight emphasizing the currently selected root branch.