An animated marker follows a wiggly SVG path while the path itself appears to draw itself in a continuous loop. The example uses D3.js version 3 to load an external SVG file via `d3.xml` and then animates both the path’s `stroke-dasharray` and the marker’s position using `transition.attrTween` and `path.getPointAtLength`. The marker is a red circle repositioned at each animation tick, while the dash array interpolation creates the synchronous drawing effect. The animation runs infinitely via a recursive transition callback.