This example shows the distributions of two variables as overlaid histograms, enabling visual comparison of their frequency shapes. The code uses d3.csv to load a dataset, then d3.histogram with 40 bins to compute counts per range for each variable. Bars are rendered as SVG rectangles with semi-transparent fills, while d3.scaleLinear and d3.axisBottom/axisLeft construct the axes. A handmade legend uses circles and text to distinguish the two series.