This example demonstrates reusable legend components for both categorical color scales and quantitative size scales. It renders four fruit categories (apple, lemon, lime, orange) using a d3.scaleOrdinal with distinct colors, alongside a d3.scaleSqrt size legend with five ticks. Both legends are built with SVG groups, circles, and text elements, using d3 selections and the .call() method to invoke the custom colorLegend and sizeLegend functions. The size legend filters out zero values and reverses tick order for visual clarity.