This example demonstrates two methods for building interactive legends in D3.js v5: a categorical color legend and a quantitative size legend. The color legend uses `scaleOrdinal` to map fruit names to distinct colors, while the size legend uses `scaleSqrt` to map a numeric range to circle radii. Both legends are rendered as SVG groups with circles and text labels, positioned via `translate` transforms. The reusable legend functions (`colorLegend` and `sizeLegend`) accept configuration objects specifying spacing, circle radius, and tick counts, allowing flexible customization within a single SVG canvas.