d3jsでかっこいいグラフ作る

以下のコードで何ができるか。。。[サンプル](http://totoman.github.io/html/index.html)

```javascript
<script>
  var links = [
    {source: "Ruby", target: "Ruby on Rails", type: "programming"},
    {source: "Vim", target: "Ruby", type: "editor"},
    {source: "NERDTree", target: "Vim", type: "editor"},
    {source: "GNU screen", target: "Vim", type: "editor"},
    {source: "JQuery", target: "Javascript", type: "front"},
    {source: "Javascript", target: "Ruby on Rails", type: "front"},
    {source: "Ajax", target: "Ruby on Rails", type: "programming"},
    {source: "React", target: "Javascript", type: "front"},
    {source: "d3js", target: "Javascript", type: "front"},
    {source: "Ubuntu", target: "Linux", type: "OS"},
    {source: "Ubuntu", target: "MacOSX", type: "OS"},
    {source: "MacOSX", target: "Linux", type: "OS"},
    {source: "MySQL", target: "Linux", type: "DB"},
    {source: "MySQL", target: "Ruby on Rails", type: "DB"},
    {source: "MongoDB", target: "Linux", type: "DB"},
    {source: "Munin", target: "Linux", type: "tool"},
    {source: "Monit", target: "Linux", type: "tool"},
    {source: "Monit", target: "Munin", type: "tool"},
    {source: "Nginx", target: "Ruby on Rails", type: "rails-server"},
    {source: "Unicorn", target: "Ruby on Rails", type: "rails-server"},
    {source: "Unicorn", target: "Nginx", type: "rails-server"},
    {source: "Capistrano", target: "Ruby on Rails", type: "rails-deploy"},
    {source: "Replication", target: "MySQL", type: "db-architecture"},
    {source: "ReplicaSet", target: "MongoDB", type: "db-architecture"},
    {source: "Sharding", target: "MongoDB", type: "db-architecture"},
    {source: "bash", target: "Linux", type: "shell"},
    {source: "zsh", target: "Linux", type: "shell"},
    {source: "zsh", target: "bash", type: "shell"},
    {source: "Ansible", target: "Linux", type: "tool"},
    {source: "AWS", target: "SAKURA", type: "server-company"},
    {source: "iTerm2", target: "Vim", type: "mac-tool"},
    {source: "Git", target: "Ruby on Rails", type: "development"},
    {source: "cron", target: "Linux", type: "tool"}
  ];
  var nodes = {};
  links.forEach(function(link) {
    link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
    link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
  });
  var width = $(window).width(),
      height = $(window).height();
  var force = d3.layout.force()
      .nodes(d3.values(nodes))
      .links(links)
      .size([width, height])
      .linkDistance(60)
      .charge(-300)
      .on("tick", tick)
      .start();
  var svg = d3.select("body").append("svg")
      .attr("width", width)
      .attr("height", height);
  var link = svg.selectAll(".link")
      .data(force.links())
    .enter().append("line")
      .attr("class", "link");
  var node = svg.selectAll(".node")
      .data(force.nodes())
    .enter().append("g")
      .attr("class", "node")
      .on("mouseover", mouseover)
      .on("mouseout", mouseout)
      .call(force.drag);
  node.append("circle")
      .attr("r", 8);
  node.append("text")
      .attr("x", 12)
      .attr("dy", ".35em")
      .attr("fill", "white")
      .text(function(d) { return d.name; });
  function tick() {
    link
        .attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });
    node
        .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
  }
  function mouseover() {
    d3.select(this).select("circle").transition()
        .duration(750)
        .attr("r", 16);
  }
  function mouseout() {
    d3.select(this).select("circle").transition()
        .duration(750)
        .attr("r", 8);
  }
</script>
```

ここみた http://bl.ocks.org/mbostock/4062045