This example demonstrates two legends: a color legend for ordinal data and a size legend for quantitative data. The color legend uses `d3.scaleOrdinal` to map fruit names to colors, while the size legend uses `d3.scaleSqrt` with five ticks to map numeric values to circle radii. Both legends are rendered as SVG groups using reusable functions that handle enter, update, and exit selections. The code relies on D3 v5’s `selection.call`, `selection.merge`, and scale methods to create interactive-looking, standalone legend components.