Three draggable circles are connected by thick black lines, with hover interactions changing the stroke style. Built with React and D3.js v7, the visualization uses `d3.drag` to handle pointer events, updating state via React's `useState` and immutable data patterns. A `VizWrapper` delegates rendering to a D3 function that uses `selectAll` and `join` to update SVG circles and lines. The initial data consists of three coordinate pairs, rendered against a full-window SVG canvas.