The example distinguishes d3.linkHorizontal and d3.linkVertical, two D3 v6 shape generators for curved node-link paths. It draws four SVG paths connecting fixed source and target points: two horizontal and two vertical variants, with green and steelblue strokes marking each type. A legend with colored rectangles labels the two generators. The code renders to an SVG canvas using React, with path geometry computed from explicit coordinate objects.