Rotating Guyou Hemispheres

Rotating Guyou hemispheres.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  padding: 22px 33px;
}

.background {
  fill: #a4bac7;
}

.foreground {
  fill: none;
  stroke: #333;
  stroke-width: 1.5px;
}

.graticule {
  fill: none;
  stroke: #fff;
  stroke-width: .5px;
}

.graticule:nth-child(2n) {
  stroke-dasharray: 2,2;
}

.land {
  fill: #d7c7ad;
  stroke: #766951;
}

.boundary {
  fill: none;
  stroke: #a5967e;
}

</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script src="https://cdn.jsdelivr.net/gh/d3/d3-plugins/geo/projection/projection.js"></script>
<script>

var width = 446,
    height = 446,
    ε = 1e-4;

var graticule = d3.geo.graticule(),
    graticule90 = d3.geo.graticule()
      .extent([[-90 + ε, -90 + ε], [90 - ε, 90 - ε]]);

var projection = d3.geo.guyou()
      .scale(120)
      .translate([width / 2 + .5, height / 2 + .5])
      .clipAngle(90 - ε),
    path = d3.geo.path().projection(projection);

var svg = d3.select("body").selectAll("svg")
    .data([{x: 0, y: 0, z: 0}, {x: 0, y: 0, z: 180}])
  .enter().append("svg")
    .attr("width", width + 1)
    .attr("height", height + 1);

svg.append("path")
    .datum(graticule90.outline)
    .attr("class", "background")
    .attr("d", path);

svg.selectAll(".graticule")
    .data(graticule.lines)
  .enter().append("path")
    .attr("class", "graticule")
    .attr("d", path);

svg.append("path")
    .datum(graticule90.outline)
    .attr("class", "foreground")
    .attr("d", path);

d3.json("readme-boundaries.json", function(err, boundaries) {
  d3.json("readme-world-countries.json", function(err, land) {
    svg.insert("g", ".graticule")
        .attr("class", "boundary")
      .selectAll("path")
        .data(boundaries.features)
      .enter().append("path");

svg.insert("g", ".graticule,.boundary")
        .attr("class", "land")
      .selectAll("path")
        .data(land.features)
      .enter().append("path");

d3.timer(function() {
      svg.call(hemisphere, boundaries, land);
    });
  });
});

function hemisphere(svg, boundaries, land) {
  svg.each(function(d, i) {
    d.z++;
    d.y += i ? -1 : 1;
    projection.rotate([d.z, d.y, 0]);
    d3.select(this).selectAll(".land path, .boundary path, .graticule")
        .attr("d", path);
  });
}

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

Updated missing url https://raw.github.com/d3/d3-plugins/master/geo/projection/projection.js to https://cdn.jsdelivr.net/gh/d3/d3-plugins/geo/projection/projection.js

https://d3js.org/d3.v3.min.js

https://raw.github.com/d3/d3-plugins/master/geo/projection/projection.js