diff --git a/samples/main-grid-topology.cc b/samples/main-grid-topology.cc
index 41ca3c638..f2837d4cf 100644
--- a/samples/main-grid-topology.cc
+++ b/samples/main-grid-topology.cc
@@ -29,7 +29,7 @@ int main (int argc, char *argv[])
   // finalize the setup by attaching to each object
   // in the input array a position and initializing
   // this position with the calculated coordinates.
-  grid.Create (nodes);
+  grid.ArrangeHorizontally (nodes);
 
 
   // iterate our nodes and print their position.
diff --git a/src/node/grid-topology.cc b/src/node/grid-topology.cc
index 3e809e324..d4e637f95 100644
--- a/src/node/grid-topology.cc
+++ b/src/node/grid-topology.cc
@@ -23,10 +23,10 @@
 
 namespace ns3 {
 
-GridTopology::GridTopology (double xMin, double yMin, uint32_t nCols, double deltaX, double deltaY)
+GridTopology::GridTopology (double xMin, double yMin, uint32_t n, double deltaX, double deltaY)
   : m_xMin (xMin),
     m_yMin (yMin),
-    m_nCols (nCols),
+    m_n (n),
     m_deltaX (deltaX),
     m_deltaY (deltaY),
     m_positionClassId (StaticPosition::cid)
@@ -39,7 +39,7 @@ GridTopology::SetPositionModel (ClassId classId)
 }
 
 void 
-GridTopology::Create (std::vector<Ptr<Object> > objects)
+GridTopology::ArrangeHorizontally (std::vector<Ptr<Object> > objects)
 {
   double x, y;
   uint32_t col;
@@ -53,7 +53,7 @@ GridTopology::Create (std::vector<Ptr<Object> > objects)
       object->AddInterface (ComponentManager::Create (m_positionClassId, x, y));
       x += m_deltaX;
       col++;
-      if (col == m_nCols)
+      if (col == m_n)
 	{
 	  col = 0;
 	  x = m_xMin;
@@ -62,4 +62,28 @@ GridTopology::Create (std::vector<Ptr<Object> > objects)
     }
 }
 
+void 
+GridTopology::ArrangeVertically (std::vector<Ptr<Object> > objects)
+{
+  double x, y;
+  uint32_t row;
+  x = m_xMin;
+  y = m_yMin;
+  row = 0;
+  for (std::vector<Ptr<Object> >::const_iterator i = objects.begin ();
+       i != objects.end (); i++)
+    {
+      Ptr<Object> object = *i;
+      object->AddInterface (ComponentManager::Create (m_positionClassId, x, y));
+      y += m_deltaY;
+      row++;
+      if (row == m_n)
+	{
+	  row = 0;
+	  y = m_yMin;
+	  x += m_deltaX;
+	}
+    }
+}
+
 } // namespace ns3
diff --git a/src/node/grid-topology.h b/src/node/grid-topology.h
index 2ff50031b..822024038 100644
--- a/src/node/grid-topology.h
+++ b/src/node/grid-topology.h
@@ -36,7 +36,7 @@ class GridTopology
   /**
    * \param xMin the left boundary where the objects will start being arranged.
    * \param yMin the lower boundary where the objects will start being arranged.
-   * \param nCols number of objects for each row
+   * \param n number of objects for each row or column
    * \param deltaX distance separating two adjacent objects along the x axis.
    * \param deltaY distance separating two adjacent objects along the y axis.
    *
@@ -56,14 +56,26 @@ class GridTopology
    * Attach a position (the type of position is specified through 
    * the ClassId given to SetPositionModel) to each object present
    * in the input vector and configure its initial location with a set
-   * of coordinates arranged according to a regular rectangular grid.
+   * of coordinates arranged according to a regular rectangular grid,
+   * one row after the other.
    */
-  void Create (std::vector<Ptr<Object> > objects);
+  void ArrangeHorizontally (std::vector<Ptr<Object> > objects);
+
+  /**
+   * \param objects a vector of objects
+   *
+   * Attach a position (the type of position is specified through 
+   * the ClassId given to SetPositionModel) to each object present
+   * in the input vector and configure its initial location with a set
+   * of coordinates arranged according to a regular rectangular grid,
+   * one column after the other.
+   */
+  void ArrangeVertically (std::vector<Ptr<Object> > objects);
  private:
   GridTopology ();
   double m_xMin;
   double m_yMin;
-  uint32_t m_nCols;
+  uint32_t m_n;
   double m_deltaX;
   double m_deltaY;
   ClassId m_positionClassId;