This is my first example using the D3 trail layout made by Benjamin Schmidt. There is no complete hellow world example yet in the official docs, so I created this one.
<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="pathlayout.js"></script>
<script>
var width = 600,
height = 500;
var points = [{"x":0,"y":0}, {"x":200,"y":200}, {"x":0,"y":400}, {"x":200,"y":100}];
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var trail = d3.layout.trail().coordType('xy');
var trail_layout = trail.data(points).layout();
paths = svg.selectAll("line").data(trail_layout);
paths.enter()
.append('line')
.style("stroke-width",3)
.style("stroke","black")
.attr("x1",function(d) {return d.x1})
.attr("y1",function(d) {return d.y1})
.attr("y2",function(d) {return d.y2})
.attr("x2",function(d) {return d.x2})
</script>