This example demonstrates two types of legends for a D3.js SVG visualization. The first legend uses a categorical color scale (`scaleOrdinal`) to map fruit names to specific colors, with circles and text labels generated by a custom `colorLegend` function. The second legend uses a square-root size scale (`scaleSqrt`) to map numeric values from 0 to 10 to varying circle radii, with ticks and labels created by a `sizeLegend` function. Both legends are built by appending groups and elements to the SVG, using D3's selection and merge methods to handle updates.