This example visualizes GDP variation for the USA and Germany over time as a scatterplot, with each country’s annual percentage change in GDP plotted against the year. A categorical color legend allows viewers to highlight or filter a specific country by clicking, which adjusts the opacity of unselected points. The visualization uses d3.scaleLinear for axes, d3.scaleOrdinal with a schemeSet2 color palette, and d3.axisBottom and d3.axisLeft for gridlines and labels. Data is loaded via d3.csv from a remote CSV file, and rendering is done using SVG elements.