This example shows the age distribution of populations across six U.S. states, with grouped bars for seven age brackets. It uses d3.csv to load the data, d3.scaleBand for the categorical axes, and d3.scaleOrdinal to assign colors to age groups. The SVG is rendered with React, and d3.axisBottom and d3.axisLeft generate the axes, while a manual legend maps color to each age range.