This example uses D3.js to create a reusable scatter plot of laptop sales data, displaying the relationship between cost and quantity sold. The chart is built with an SVG-based custom scatter plot API that constructs axes, labels, and title using `scaleLinear`, `extent`, `axisLeft`, and `axisBottom`. Each point is rendered as a steelblue circle with a radius of six pixels and 70 percent opacity. The code loads a CSV file from a GitHub Gist, parses it, and then applies the plot to a full-window SVG.