This example uses D3.js v4 to render a hierarchical tree visualization of educational data from Santander, Colombia. The data, loaded from a CSV file, contains a hierarchy of regions, school levels, and gender-specific enrollment counts. The visualization employs an animated radial tree layout, with internal nodes highlighted in red and leaf nodes in blue. Hovering or interacting with the nodes reveals the nested structure, and the animation brings the hierarchy to life. The title "positive definite" hints at the mathematical concept of positive definiteness, reflecting the organized, tree-like aggregation of data. The SVG-based rendering uses distinct colors and text shadows to differentiate internal from leaf nodes, making the hierarchy easy to explore.