diff --git a/bounded-voronoi.html b/bounded-voronoi.html
new file mode 100644
index 0000000..f65b3d1
--- /dev/null
+++ b/bounded-voronoi.html
@@ -0,0 +1,186 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<style>
+
+.links {
+  stroke: #000;
+  stroke-opacity: 0;
+}
+
+.polygons {
+  stroke: #fff;
+}
+
+.polygons :first-child {
+  fill: #ff3d5a;
+}
+
+.sites {
+  fill: none;
+  stroke: none;
+}
+
+.sites :first-child {
+  fill: #fff;
+}
+
+.convex-hull {
+  fill: none;
+  stroke: #feccd5;
+  stroke-width: 5px;
+}
+
+</style>
+<svg width="960" height="800"></svg>
+<script src="https://d3js.org/d3.v4.min.js"></script>
+<script src="https://d3js.org/d3-scale-chromatic.v1.min.js"></script>
+<script>
+
+var sourcedata = [ 100, 100, 200, 130, 400, 150, 160, 170, 130, 900, 100, 1000, 200, 130, 40, 150, 160, 170, 130 ];
+
+var svg = d3.select("svg"),
+width = +svg.attr("width"),
+height = +svg.attr("height"),
+margin = 0.4; // 0 ≤ m < 0.5
+
+var color = d3.scaleOrdinal(d3.schemePastel1),
+line = d3.line().curve(d3.curveCatmullRomClosed);
+
+function makeData (inputData) {
+  var outputData = [];
+  // First sum all the values. Then calculate a percentage of the whole.
+  var sum = inputData.reduce(function(acc, val) {
+    return acc + val;
+  }, 0);
+
+  // Now turn the single data point into a pair of length, angle
+  for (var i = 0; i < inputData.length; i++) {
+    // calc the percentage
+    var value = 5 * inputData[i] / sum;
+
+    // calculate length and angle from that percentage
+    var len = Math.min(width, height) / 2 *
+        (1 - margin) * Math.sqrt(value);
+    var angle = value * 2 * Math.PI;
+
+    // stick the length and angle into the output data
+    outputData[i] = [ width / 2 + len * Math.cos(angle),
+      height / 2 + len * Math.sin(angle) ];
+    }
+    return outputData;
+  }
+
+  var sites = makeData( sourcedata );
+
+  var voronoi = d3.voronoi()
+  .extent([[-1, -1], [width + 1, height + 1]]);
+
+  var convexhull = svg.append('path')
+  .attr('class', 'convex-hull');
+
+  var polygon = svg.append("g")
+  .attr("class", "polygons");
+
+  var link = svg.append("g")
+  .attr("class", "links");
+
+  var site = svg.append("g")
+  .attr("class", "sites");
+
+  redraw();
+
+  function moved() {
+    sites[0] = d3.mouse(this);
+    redraw();
+  }
+
+  function redraw() {
+
+    var links = voronoi.links(sites),
+    ext = Math.sqrt(d3.median(links, function(l) {
+      var dx = l.source[0] - l.target[0],
+      dy = l.source[1] - l.target[1];
+      return dx*dx + dy*dy;
+    }));
+
+    var convex = d3.polygonHull(sites);
+    convex.centroid = d3.polygonCentroid(convex);
+    convex = convex.map(function(p){
+      var dx = p[0] - convex.centroid[0],
+      dy = p[1] - convex.centroid[1],
+      angle = Math.atan2(dy, dx);
+      return [p[0] + Math.cos(angle) * ext, p[1] + Math.sin(angle) * ext];
+    });
+
+    var sites2 = sites.slice(); // clone
+    for (var i = 0; i < convex.length; i++) {
+      var n = convex[i], m = convex[i+1]||convex[0];
+      var dx = n[0] - m[0],
+      dy = n[1] - m[1],
+      dist = Math.sqrt(dx * dx + dy * dy);
+      var pts = 10 * Math.ceil(dist / 2 / ext);
+      for(var j=0; j <= pts; j++) {
+        var p = [m[0] + dx *j / pts, m[1] + dy * j / pts];
+        p.artificial = 1;
+        sites2.push(p);
+      }
+    }
+
+    var diagram = voronoi(sites2);
+
+    var p = polygon.selectAll("path")
+    .data(diagram.polygons());
+    p.enter().append("path").merge(p).call(redrawPolygon)
+    p.exit().remove();
+
+    var l = link
+    .selectAll("line")
+    .data(diagram.links().filter(function(l){
+      return !l.source.artificial && !l.target.artificial;
+    }));
+    l.enter()
+    .append("line")
+    .merge(l)
+    .call(redrawLink)
+    .exit()
+    .remove();
+
+    var s = site
+    .selectAll("circle")
+    .data(sites);
+    s.enter()
+    .append("circle")
+    .attr("r", 2.5)
+    .merge(s)
+    .call(redrawSite);
+
+    convexhull.attr('d', line(convex));
+
+  }
+
+  function redrawPolygon(polygon) {
+    polygon
+    .attr("fill", function(d, i) {
+      return i < sites.length ? color(i) : 'none';
+    })
+    .attr("stroke-width", function(d, i) {
+      return i < sites.length ? 2 : 0;
+    })
+    .attr("d", function(d) { return d ? "M" + d.join("L") + "Z" : null; });
+  }
+
+  function redrawLink(link) {
+    link
+    .attr("x1", function(d) { return d.source[0]; })
+    .attr("y1", function(d) { return d.source[1]; })
+    .attr("x2", function(d) { return d.target[0]; })
+    .attr("y2", function(d) { return d.target[1]; });
+  }
+
+  function redrawSite(site) {
+    site
+    .attr("cx", function(d) { return d[0]; })
+    .attr("cy", function(d) { return d[1]; });
+  }
+
+  </script>
diff --git a/voronoi.html b/voronoi.html
new file mode 100644
index 0000000..46fd04e
--- /dev/null
+++ b/voronoi.html
@@ -0,0 +1,79 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<canvas width="960" height="500"></canvas>
+<script src="https://d3js.org/d3.v4.min.js"></script>
+<script>
+
+var canvas = d3.select("canvas").on("touchmove mousemove", moved).node(),
+    context = canvas.getContext("2d"),
+    width = canvas.width,
+    height = canvas.height;
+
+var sites = d3.range(100)
+    .map(function(d) { return [Math.random() * width, Math.random() * height]; });
+
+var voronoi = d3.voronoi()
+    .extent([[-1, -1], [width + 1, height + 1]]);
+
+redraw();
+
+function moved() {
+  sites[0] = d3.mouse(this);
+  redraw();
+}
+
+function redraw() {
+  var diagram = voronoi(sites),
+      links = diagram.links(),
+      polygons = diagram.polygons();
+
+  context.clearRect(0, 0, width, height);
+  context.beginPath();
+  drawCell(polygons[0]);
+  context.fillStyle = "#f00";
+  context.fill();
+
+  context.beginPath();
+  for (var i = 0, n = polygons.length; i < n; ++i) drawCell(polygons[i]);
+  context.strokeStyle = "#000";
+  context.stroke();
+
+  context.beginPath();
+  for (var i = 0, n = links.length; i < n; ++i) drawLink(links[i]);
+  context.strokeStyle = "rgba(0,0,0,0.2)";
+  context.stroke();
+
+  context.beginPath();
+  drawSite(sites[0]);
+  context.fillStyle = "#fff";
+  context.fill();
+
+  context.beginPath();
+  for (var i = 1, n = sites.length; i < n; ++i) drawSite(sites[i]);
+  context.fillStyle = "#000";
+  context.fill();
+  context.strokeStyle = "#fff";
+  context.stroke();
+}
+
+function drawSite(site) {
+  context.moveTo(site[0] + 2.5, site[1]);
+  context.arc(site[0], site[1], 2.5, 0, 2 * Math.PI, false);
+}
+
+function drawLink(link) {
+  context.moveTo(link.source[0], link.source[1]);
+  context.lineTo(link.target[0], link.target[1]);
+}
+
+function drawCell(cell) {
+  if (!cell) return false;
+  context.moveTo(cell[0][0], cell[0][1]);
+  for (var j = 1, m = cell.length; j < m; ++j) {
+    context.lineTo(cell[j][0], cell[j][1]);
+  }
+  context.closePath();
+  return true;
+}
+
+</script>
