This example shows a scatter plot of age versus insurance charges, with points shaped by sex and a legend for gender. The plot uses D3 v7 APIs including `scaleLinear`, `scaleOrdinal`, `symbolsFill`, and `symbol` to generate shapes, along with custom axis and legend modules. Data is loaded as CSV from a GitHub gist and parsed with `csvParse`. The SVG chart resizes to the viewport, and the axes and legend are drawn using D3's `axisLeft` and `axisBottom` helpers.