This example visualizes car sales data with two charts. The first is an area chart of selling price over time, using a time-based x-axis and a linear y-axis. The second is a smoothed line chart showing the average selling price aggregated by 10,000-mile odometer intervals. Both charts are rendered as SVG using D3’s `select`, `scaleTime`, `scaleLinear`, `area`, `line`, `curveBasis`, and `mean` APIs. The data is loaded from a remote CSV file.