D3rt is an interactive particle-based visualization that assembles points into a yellow smiley face with black eyes and a curved mouth. The example uses D3’s force simulation (`d3.forceSimulation`) to position and move particles toward target coordinates defined in an SVG circle and eye shapes. Rendered on a full-screen canvas, the particles converge from a chaotic state into the face pattern, demonstrating a simple flocking or clustering effect. The code references the `cx`, `cy`, and `r` attributes from the SVG markup as the final formation targets.