This scatter plot visualizes the relationship between horsepower and weight for cars from the UCI Machine Learning Repository’s Auto MPG dataset, with each point colored by the car’s country of origin (USA, Japan, or Germany). Clicking a country in the color legend filters the points by toggling their opacity, highlighting cars from that origin. Built with D3 v5, the visualization uses `scaleLinear`, `axisBottom`, `axisLeft`, and `scaleOrdinal` to render SVG axes and circles, while the legend relies on `d3.legendColor` for a horizontal color scale.