This example shows a tree diagram with nodes that can have multiple parents, using data about related concepts like "Supply and demand" and "Foreign worker." The visualization repositions nodes to avoid duplication, calculating new coordinates after filtering unique nodes by ID. It uses D3's `tree` layout, `linkHorizontal` path generator, and a custom zoom interaction via the `zoom` event. The SVG text nodes and links are animated with transitions, with links colored based on a selected state.