This example shows the relationship between car price and mileage with an interactive scatter plot. Each circle represents a vehicle, positioned by mileage on the x-axis and price on the y-axis, with color encoding price ranges via a `d3.scaleThreshold` (green, yellow, orange, red). Hovering over a point enlarges the circle and reveals the make, model, and price in a temporary text tooltip. The chart uses `d3.csv` to load external data and renders axes and circles as SVG, with a legend summarizing price bins.