This example shows a hierarchical cluster dendrogram of machine learning research topics, using a tidy tree layout where each leaf node represents a specific topic and branches group related subtopics. The visualization uses `d3.cluster` to position nodes and `d3.stratify` to build the tree structure from CSV data with hierarchical id fields. Curved link paths create the classic dendrogram appearance, with internal nodes labeled on the left and leaf labels on the right. Data comes from a flare.csv file containing nested topic names, rendered as SVG elements with circle markers and text labels.