This example shows temperature readings from multiple cities over one week, using smooth curved lines to compare trends. The visualization renders as an SVG with D3 v5, using `d3.scaleTime` and `d3.scaleLinear` for axes, `d3.line` with `curveBasis` for path generation, and `d3.nest` to group data by city. A custom color legend component is imported from a separate module, while data loads from a CSV containing timestamps and temperatures.