This example animates a set of randomly moving points and their evolving density contours. Using the Old Faithful geyser dataset, it visualizes how the point distribution shifts over time. The code employs `d3.contourDensity()` to compute contour levels and `d3.geoPath()` to render them as SVG paths. Points drift randomly within the canvas, and each contour is filled with a random color and outlined in steel blue. The visualization updates every 200 milliseconds using `d3.interval`, creating a dynamic, fluid representation of changing data density.