This example displays a hierarchical tree representing user interaction with a learning task. Starting at a root node, it branches into whether the task was visited, attempted, and ultimately answered correctly or incorrectly, with each node distinctly colored. Users can click any node to collapse or expand its children, with smooth animated transitions. The visualization uses D3 v5’s `tree()` layout and `linkHorizontal()` generator, rendering SVG rectangles and text, with zoom functionality enabled through `d3.zoom`.