This example shows a world map with a graticule and a rectangular polygon overlay, rendered as SVG paths. Users can drag to rotate the projection and zoom to rescale the view. It uses `d3.geoEquirectangular` with `d3.geoClipPolygon` to clip the sphere, `d3.geoGraticule` for the grid, and `d3.geoPath` for rendering. Country boundaries come from TopoJSON data in the world-atlas package, with drag handling via `d3.drag` and zoom via `d3.zoom`. The polygon overlay is outlined via `arc.outline()`.