addded line for vtk (old code)

src/Plot.C

@@ -372,6 +372,9 @@ void Plot::vtk_mesh(ostream &out, int deform) {
     for (int i = 0; i < C.size(); ++i, out << endl) {
         out << C[i].size() << " ";
         switch (C[i].size()) {
+            case 2:
+                out << C[i][0] << " " << C[i][1];
+                break;
             case 3:
                 out << C[i][0] << " " << C[i][1] << " " << C[i][2];
                 break;
@@ -391,6 +394,9 @@ void Plot::vtk_mesh(ostream &out, int deform) {
     out << "CELL_TYPES " << C.size() << endl;
     for (int i = 0; i < C.size(); ++i, out << endl) {
         switch (C[i].size()) {
+            case 2:
+                out << "3";
+                break;
             case 3:
                 out << "5";
                 break;
@@ -433,6 +439,9 @@ void Plot::vtk_2d_graph(ostream &out, int k) {
     out << "CELL_TYPES " << C.size() << endl;
     for (int i = 0; i < C.size(); ++i, out << endl) {
         switch (C[i].size()) {
+            case 2:
+                out << "3";
+                break;
             case 3:
                 out << "5";
                 break;