diff --git a/src/geo/stream-buffer.js b/src/geo/stream-buffer.js
index 8c95f61e..fd63826e 100644
--- a/src/geo/stream-buffer.js
+++ b/src/geo/stream-buffer.js
@@ -1,43 +1,38 @@
-function d3_geo_streamBuffer() {
-  this._buffer = [];
-  this._point = d3_geo_pathCircle(4.5);
-}
+function d3_geo_streamBuffer(buffer, pointRadius) {
+  var stream = {
+    point: point,
 
-d3_geo_streamBuffer.prototype = {
-  point: d3_geo_streamBufferPoint,
+    // While inside a line, override point to moveTo then lineTo.
+    lineStart: function() { stream.point = pointLineStart; },
+    lineEnd: lineEnd,
 
-  // While inside a line, override point to moveTo then lineTo.
-  lineStart: function() { this.point = d3_geo_streamBufferPointLineStart; },
-  lineEnd: d3_geo_streamBufferLineEnd,
+    // While inside a polygon, override lineEnd to closePath.
+    polygonStart: function() { stream.lineEnd = lineEndPolygon; },
+    polygonEnd: function() { stream.lineEnd = lineEnd; }
+  };
 
-  // While inside a polygon, override lineEnd to closePath.
-  polygonStart: function() { this.lineEnd = d3_geo_streamBufferLineEndPolygon; },
-  polygonEnd: function() { this.lineEnd = d3_geo_streamBufferLineEnd; },
-
-  toString: function() {
-    var s = this._buffer.join("");
-    this._buffer = [];
-    return s;
+  function point(x, y) {
+    buffer.push("M", x, ",", y, pointRadius);
   }
-};
 
-function d3_geo_streamBufferPoint(x, y) {
-  this._buffer.push("M", x, ",", y, this._point);
-}
+  function pointLineStart(x, y) {
+    buffer.push("M", x, ",", y);
+    stream.point = pointLine;
+  }
 
-function d3_geo_streamBufferPointLineStart(x, y) {
-  this._buffer.push("M", x, ",", y);
-  this.point = d3_geo_streamBufferPointLine;
-}
+  function pointLine(x, y) {
+    buffer.push("L", x, ",", y);
+  }
 
-function d3_geo_streamBufferPointLine(x, y) {
-  this._buffer.push("L", x, ",", y);
-}
+  function lineEnd() {
+    stream.point = point;
+  }
 
-function d3_geo_streamBufferLineEnd() {
-  this.point = d3_geo_streamBufferPoint;
-}
+  function lineEndPolygon() {
+    buffer.push("Z");
+  }
 
-function d3_geo_streamBufferLineEndPolygon() {
-  this._buffer.push("Z");
+  pointRadius = d3_geo_pathCircle(4.5);
+
+  return stream;
 }
diff --git a/src/geo/stream-context.js b/src/geo/stream-context.js
index 5b6aeb5a..472c446d 100644
--- a/src/geo/stream-context.js
+++ b/src/geo/stream-context.js
@@ -1,37 +1,37 @@
-function d3_geo_streamContext() {
-  this._pointRadius = 4.5;
-}
-
-d3_geo_streamContext.prototype = {
-  point: d3_geo_streamContextPoint,
-
-  // While inside a line, override point to moveTo then lineTo.
-  lineStart: function() { this.point = d3_geo_streamContextPointLineStart; },
-  lineEnd: d3_geo_streamContextLineEnd,
-
-  // While inside a polygon, override lineEnd to closePath.
-  polygonStart: function() { this.lineEnd = d3_geo_streamContextLineEndPolygon; },
-  polygonEnd: function() { this.lineEnd = d3_geo_streamContextLineEnd; }
-};
-
-function d3_geo_streamContextPoint(x, y) {
-  this._context.moveTo(x, y);
-  this._context.arc(x, y, this._pointRadius, 0, 2 * π);
-}
-
-function d3_geo_streamContextPointLineStart(x, y) {
-  this._context.moveTo(x, y);
-  this.point = d3_geo_streamContextPointLine;
-}
-
-function d3_geo_streamContextPointLine(x, y) {
-  this._context.lineTo(x, y);
-}
-
-function d3_geo_streamContextLineEnd() {
-  this.point = d3_geo_streamContextPoint;
-}
-
-function d3_geo_streamContextLineEndPolygon() {
-  this._context.closePath();
+function d3_geo_streamContext(context, pointRadius) {
+  var stream = {
+    point: point,
+
+    // While inside a line, override point to moveTo then lineTo.
+    lineStart: function() { stream.point = pointLineStart; },
+    lineEnd: lineEnd,
+
+    // While inside a polygon, override lineEnd to closePath.
+    polygonStart: function() { stream.lineEnd = lineEndPolygon; },
+    polygonEnd: function() { stream.lineEnd = lineEnd; }
+  };
+
+  function point(x, y) {
+    context.moveTo(x, y);
+    context.arc(x, y, pointRadius, 0, 2 * π);
+  }
+
+  function pointLineStart(x, y) {
+    context.moveTo(x, y);
+    stream.point = pointLine;
+  }
+
+  function pointLine(x, y) {
+    context.lineTo(x, y);
+  }
+
+  function lineEnd() {
+    stream.point = point;
+  }
+
+  function lineEndPolygon() {
+    context.closePath();
+  }
+
+  return stream;
 }
diff --git a/src/geo/stream-radians.js b/src/geo/stream-radians.js
new file mode 100644
index 00000000..b7681140
--- /dev/null
+++ b/src/geo/stream-radians.js
@@ -0,0 +1,5 @@
+function d3_geo_streamRadians(stream) {
+  return d3_geo_streamTransform(stream, function(x, y) {
+    stream.point(x * d3_radians, y * d3_radians);
+  });
+}
diff --git a/src/geo/stream-rotate.js b/src/geo/stream-rotate.js
new file mode 100644
index 00000000..a8a19f1e
--- /dev/null
+++ b/src/geo/stream-rotate.js
@@ -0,0 +1,6 @@
+function d3_geo_streamRotate(rotate, stream) {
+  return d3_geo_streamTransform(stream, function(x, y) {
+    x = rotate(x, y);
+    stream.point(x[0], x[1]);
+  });
+}
diff --git a/src/geo/stream-transform.js b/src/geo/stream-transform.js
new file mode 100644
index 00000000..ee10c349
--- /dev/null
+++ b/src/geo/stream-transform.js
@@ -0,0 +1,10 @@
+function d3_geo_streamTransform(stream, point) {
+  return {
+    point: point,
+    sphere: stream.sphere,
+    lineStart: stream.lineStart,
+    lineEnd: stream.lineEnd,
+    polygonStart: stream.polygonStart,
+    polygonEnd: stream.polygonEnd
+  };
+}