This example demonstrates how to create color and size legends in D3 v5 using reusable functions. It shows ordinal color scaling mapping fruit names to pastel colors, and a square-root size scale with transitioning circles. The SVG rendering includes animated transitions on the size legend, while text labels accompany each legend entry. The code uses `d3.scaleOrdinal`, `d3.scaleSqrt`, and D3's selection join pattern with `.enter()` and `.merge()`.