This example shows a hierarchical student data tree with nodes for a Student, Course, Name, Course variants, Grades, and First/Last Name, each color-coded by generation depth. It uses d3.stratify to structure the flat data array, d3.tree to compute node positions, and SVG circles and text to render the nodes. The code animates the links with a transition that moves each path from its source to target position over 1.5 seconds, while node circles also transition their radius.