diff --git a/README.md b/README.md
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+# Multipart Sankey Diagrams
+
+Extended from Mike Bostock's original d3.sankey.
+
+[Demo](http://bl.ocks.org/emeeks/1dd092dadc02a93cdebc)
+
+```js
+var sankey = d3.sankey()
+    .size([width, height])
+    .nodeWidth(15)
+    .nodePadding(10)
+    .nodes(energy.nodes)
+    .links(energy.links)
+    .layout(32);
+```
+
+```
+var path = sankey.link();
+```
diff --git a/sankey.js b/sankey.js
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+d3.sankey = function() {
+  var sankey = {},
+      nodeWidth = 24,
+      nodePadding = 8,
+      size = [1, 1],
+      nodes = [],
+      links = [];
+
+  sankey.nodeWidth = function(_) {
+    if (!arguments.length) return nodeWidth;
+    nodeWidth = +_;
+    return sankey;
+  };
+
+  sankey.nodePadding = function(_) {
+    if (!arguments.length) return nodePadding;
+    nodePadding = +_;
+    return sankey;
+  };
+
+  sankey.nodes = function(_) {
+    if (!arguments.length) return nodes;
+    nodes = _;
+    return sankey;
+  };
+
+  sankey.links = function(_) {
+    if (!arguments.length) return links;
+    links = _;
+    return sankey;
+  };
+
+  sankey.size = function(_) {
+    if (!arguments.length) return size;
+    size = _;
+    return sankey;
+  };
+
+  sankey.layout = function(iterations) {
+    computeNodeLinks();
+    computeNodeValues();
+    computeNodeBreadths();
+    computeNodeDepths(iterations);
+    computeLinkDepths();
+    return sankey;
+  };
+
+  sankey.relayout = function() {
+    computeLinkDepths();
+    return sankey;
+  };
+
+  sankey.linkAdjusted = function() {
+    var curvature = .5;
+
+    function link(d, adjustment, segmentOffset) {
+      var x0 = d.source.x + d.source.dx,
+          x1 = d.target.x,
+          xi = d3.interpolateNumber(x0, x1),
+          x2 = xi(curvature),
+          x3 = xi(1 - curvature),
+          y0 = d.source.y + d.sy + segmentOffset,
+          y1 = d.target.y + d.ty + segmentOffset,
+          y2 = d.target.y + d.ty + (d.dy * adjustment) + segmentOffset,
+          y3 = d.source.y + d.sy + (d.dy * adjustment) + segmentOffset;
+
+      return "M" + x0 + "," + y0
+           + "C" + x2 + "," + y0
+           + " " + x3 + "," + y1
+           + " " + x1 + "," + y1
+           + "L" + x1 + "," + y2
+           + "C" + x3 + "," + y2
+           + " " + x2 + "," + y3
+           + " " + x0 + "," + y3
+           + "Z";
+    }
+
+    link.curvature = function(_) {
+      if (!arguments.length) return curvature;
+      curvature = +_;
+      return link;
+    };
+
+    return link;
+  };
+
+  sankey.link = function() {
+    var curvature = .5;
+
+    function link(d) {
+      var x0 = d.source.x + d.source.dx,
+          x1 = d.target.x,
+          xi = d3.interpolateNumber(x0, x1),
+          x2 = xi(curvature),
+          x3 = xi(1 - curvature),
+          y0 = d.source.y + d.sy,
+          y1 = d.target.y + d.ty,
+          y2 = d.target.y + d.ty + d.dy,
+          y3 = d.source.y + d.sy + d.dy;
+
+      if (y3 - y0 < 30000) {
+
+      return "M" + x0 + "," + y0
+           + "C" + x2 + "," + y0
+           + " " + x3 + "," + y1
+           + " " + x1 + "," + y1
+           + "L" + x1 + "," + y2
+           + "C" + x3 + "," + y2
+           + " " + x2 + "," + y3
+           + " " + x0 + "," + y3
+           + "Z";
+         }
+         else {
+
+          var offset = (x1 - x0) /4;
+      return "M" + x0 + "," + y0
+           + "C" + x2 + "," + y0
+           + " " + x3 + "," + (y1)
+           + " " + (x1 - offset) + "," + (y1 + 0)
+           + "L" + (x1 - 6) + "," + ((y2 + y1)/2)
+           + "L" + (x1 - offset) + "," + (y2 + 0)
+           + "C" + x3 + "," + (y2)
+           + " " + x2 + "," + y3
+           + " " + x0 + "," + y3
+           + "Z";
+
+         }
+    }
+
+    link.curvature = function(_) {
+      if (!arguments.length) return curvature;
+      curvature = +_;
+      return link;
+    };
+
+    return link;
+  };
+
+  // Populate the sourceLinks and targetLinks for each node.
+  // Also, if the source and target are not objects, assume they are indices.
+  function computeNodeLinks() {
+    nodes.forEach(function(node) {
+      node.sourceLinks = [];
+      node.targetLinks = [];
+    });
+    links.forEach(function(link) {
+      var source = link.source,
+          target = link.target;
+      if (typeof source === "number") source = link.source = nodes[link.source];
+      if (typeof target === "number") target = link.target = nodes[link.target];
+      source.sourceLinks.push(link);
+      target.targetLinks.push(link);
+    });
+  }
+
+  // Compute the value (size) of each node by summing the associated links.
+  function computeNodeValues() {
+    nodes.forEach(function(node) {
+      node.value = Math.max(
+        d3.sum(node.sourceLinks, value),
+        d3.sum(node.targetLinks, value)
+      );
+    });
+  }
+
+  // Iteratively assign the breadth (x-position) for each node.
+  // Nodes are assigned the maximum breadth of incoming neighbors plus one;
+  // nodes with no incoming links are assigned breadth zero, while
+  // nodes with no outgoing links are assigned the maximum breadth.
+  function computeNodeBreadths() {
+
+    var remainingNodes = nodes,
+        nextNodes,
+        x = 0;
+
+    while (remainingNodes.length) {
+      nextNodes = [];
+      remainingNodes.forEach(function(node) {
+        node.x = x;
+        node.dx = nodeWidth;
+        node.sourceLinks.forEach(function(link) {
+          if (nextNodes.indexOf(link.target) < 0) {
+            nextNodes.push(link.target);
+          }
+        });
+      });
+      remainingNodes = nextNodes;
+      ++x;
+    }
+
+    moveSinksRight(x);
+    scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
+  }
+
+  function moveSourcesRight() {
+    nodes.forEach(function(node) {
+      if (!node.targetLinks.length) {
+        node.x = d3.min(node.sourceLinks, function(d) { return d.target.x; }) - 1;
+      }
+    });
+  }
+
+  function moveSinksRight(x) {
+    nodes.forEach(function(node) {
+      if (!node.sourceLinks.length) {
+        node.x = x - 1;
+      }
+    });
+  }
+
+  function scaleNodeBreadths(kx) {
+    nodes.forEach(function(node) {
+      node.x *= kx;
+    });
+  }
+
+  function computeNodeDepths(iterations) {
+    var nodesByBreadth = d3.nest()
+        .key(function(d) { return d.x; })
+        .sortKeys(d3.ascending)
+        .entries(nodes)
+        .map(function(d) { return d.values; });
+
+    //
+    initializeNodeDepth();
+    resolveCollisions();
+    for (var alpha = 1; iterations > 0; --iterations) {
+      relaxRightToLeft(alpha *= .99);
+      resolveCollisions();
+      relaxLeftToRight(alpha);
+      resolveCollisions();
+    }
+
+    function initializeNodeDepth() {
+      var ky = d3.min(nodesByBreadth, function(nodes) {
+        return (size[1] - (nodes.length - 1) * nodePadding) / d3.sum(nodes, value);
+      });
+
+      nodesByBreadth.forEach(function(nodes) {
+        nodes.forEach(function(node, i) {
+          node.y = i;
+          node.dy = node.value * ky;
+        });
+      });
+
+      links.forEach(function(link) {
+        link.dy = link.value * ky;
+      });
+    }
+
+    function relaxLeftToRight(alpha) {
+      nodesByBreadth.forEach(function(nodes, breadth) {
+        nodes.forEach(function(node) {
+          if (node.targetLinks.length) {
+            var y = d3.sum(node.targetLinks, weightedSource) / d3.sum(node.targetLinks, value);
+            node.y += (y - center(node)) * alpha;
+          }
+        });
+      });
+
+      function weightedSource(link) {
+        return center(link.source) * link.value;
+      }
+    }
+
+    function relaxRightToLeft(alpha) {
+      nodesByBreadth.slice().reverse().forEach(function(nodes) {
+        nodes.forEach(function(node) {
+          if (node.sourceLinks.length) {
+            var y = d3.sum(node.sourceLinks, weightedTarget) / d3.sum(node.sourceLinks, value);
+            node.y += (y - center(node)) * alpha;
+          }
+        });
+      });
+
+      function weightedTarget(link) {
+        return center(link.target) * link.value;
+      }
+    }
+
+    function resolveCollisions() {
+      nodesByBreadth.forEach(function(nodes) {
+        var node,
+            dy,
+            y0 = 0,
+            n = nodes.length,
+            i;
+
+        // Push any overlapping nodes down.
+        nodes.sort(ascendingDepth);
+        for (i = 0; i < n; ++i) {
+          node = nodes[i];
+          dy = y0 - node.y;
+          if (dy > 0) node.y += dy;
+          y0 = node.y + node.dy + nodePadding;
+        }
+
+        // If the bottommost node goes outside the bounds, push it back up.
+        dy = y0 - nodePadding - size[1];
+        if (dy > 0) {
+          y0 = node.y -= dy;
+
+          // Push any overlapping nodes back up.
+          for (i = n - 2; i >= 0; --i) {
+            node = nodes[i];
+            dy = node.y + node.dy + nodePadding - y0;
+            if (dy > 0) node.y -= dy;
+            y0 = node.y;
+          }
+        }
+      });
+    }
+
+    function ascendingDepth(a, b) {
+      return a.y - b.y;
+    }
+  }
+
+  function computeLinkDepths() {
+    nodes.forEach(function(node) {
+      node.sourceLinks.sort(ascendingTargetDepth);
+      node.targetLinks.sort(ascendingSourceDepth);
+    });
+    nodes.forEach(function(node) {
+      var sy = 0, ty = 0;
+      node.sourceLinks.forEach(function(link) {
+        link.sy = sy;
+        sy += link.dy;
+      });
+      node.targetLinks.forEach(function(link) {
+        link.ty = ty;
+        ty += link.dy;
+      });
+    });
+
+    function ascendingSourceDepth(a, b) {
+      return a.source.y - b.source.y;
+    }
+
+    function ascendingTargetDepth(a, b) {
+      return a.target.y - b.target.y;
+    }
+  }
+
+  function center(node) {
+    return node.y + node.dy / 2;
+  }
+
+  function value(link) {
+    return link.value;
+  }
+
+  return sankey;
+};
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