A circular moon rendered in black and white rotates across the screen, with a dark cratered sphere against a pitch-black background. The visualization uses D3 v4’s `d3.geoOrthographic` projection and `d3.geoPath` to draw the moon as a geographic circle, while `d3.timer` drives an animation that shifts the circle’s center over time, simulating rotation. Two SVG paths—one for the moon’s body and one for its background—are updated each frame. The code defines no external data source, instead generating the shape procedurally with `d3.geoCircle`.