This example visualizes the relationship between fuel efficiency, horsepower, weight, and country of origin for cars from the UCI Auto MPG dataset. The scatter plot encodes miles per gallon on the x-axis, horsepower on the y-axis, color by origin, and point size by weight. It is built with the Vega-Lite API, which registers Vega, Vega-Lite, and Vega-Tooltip to render an interactive SVG chart. Data is loaded asynchronously via D3’s `csv` function, while the visualization code uses `vl.markCircle`, `.encode`, and `vl.x().fieldQ()` to define the marks and scales.