This example visualizes eye color data by binding a JSON dataset to SVG circles, each positioned sequentially along the x-axis and colored according to a validated hex color value. The code loads data with `d3.json`, filters invalid colors using a regex, parses hex values into RGB components, and sorts the data before rendering. It demonstrates basic data joins with `svg.selectAll().data().enter().append()` without using scales, keeping circle positions and radii fixed.