fresh block
A circular chord diagram visualizes a 7x7 matrix of directed relationships among seven entities, with arc lengths and ribbon widths proportional to the values. The SVG rendering uses D3 v4's `d3.chord` layout, with `d3.arc` and `d3.ribbon` generating the shapes, and a `d3.scaleOrdinal` color palette. Ticks are labeled with names from a hardcoded array, while tick placement relies on a custom `groupTicks` function. The data is a fixed in-memory matrix, not loaded from an external file.