This chord diagram visualizes directed relationships among four hair-color groups using a matrix of interaction values. Built with D3 v7, it renders arcs for each group and ribbons showing bidirectional flows, with hover highlighting related chords and click-to-select filtering. The visualization uses `d3.chord`, `d3.arc`, and `d3.ribbon` generators, includes tick marks with formatted value labels, and displays tooltips on both arcs and ribbons. Data originates from a static 4x4 matrix with named groups and custom colors, ported from an Observable notebook to vanilla JavaScript.