Based on the D3.js code provided, this appears to be creating a Voronoi diagram with color gradients and text overlay. Here are the key components:

1. Setup:



var width = 600;  
var height = 400;  
var samples = 200;

2. SVG Container Creation:



var container = d3.select("body")  
  .append("div")  
  .classed("svg-container", true);  
  
var svg = container  
  .append("svg")  
  .attr("preserveAspectRatio", "xMinYMin meet")  
  .attr("viewBox", "0 0 " + width + " " + height);

3. Data Generation:



var sites = d3.range(samples)  
  .map(() => [Math.random() * width, Math.random() * height]);

4. Voronoi Computation:



var voronoi = d3.Delaunay.from(sites)  
  .voronoi([-1, -1, width + 1, height + 1]);

5. Color Function:



function color(d) {  
  var dx = d[0][0] - width / 2,  
      dy = d[1][0] - height / 2;  
  return d3.lab(  
    100 - (dx * dx + dy * dy) / 5000,   
    dx / 10,   
    dy / 10  
  );  
}

The code creates a responsive SVG containing Voronoi cells with a color gradient emanating from the center, and "D3" text displayed in the middle. The coloring is based on the distance from the center point.