This example demonstrates how D3 v3 renders SVG marker shapes used as line endpoints. It defines four distinct path geometries—circle, square, arrow, and stub—and attaches each as both a marker-start and marker-end to a corresponding element in a group. The code uses `d3.scale.category10` for colors, builds markers via SVG `<defs>`, and positions everything within a fixed margin layout. The visible result is a set of colored, marker-capped paths across the canvas, though the intended connecting lines are commented out.