This example displays a scatter plot of happiness survey data, plotting age on the x-axis against income on the y-axis. Each point is colored according to the reported happiness level (High, Medium, or Low) using a custom color mapping. The visualization is rendered as an SVG using D3 v6, with data loaded from a remote CSV file via `d3.csv`. Axes are generated using `d3.axisLeft` and `d3.axisBottom`, while linear scales are created with `d3.scaleLinear`.