This treemap demo shows a hierarchical dataset of a CEO’s employees, grouped into three boss-level parents, with each leaf rectangle sized by its numeric value. The interface includes buttons to mutate the data: changing leaf values, adding or removing child nodes, and adding or removing entire parent groups. The visualization updates with animated transitions on rectangles and text labels, rendered in SVG via React. It uses d3.hierarchy and d3.treemap for layout, d3.scaleOrdinal for color coding by parent, and d3.scaleLinear for opacity based on value.