diff --git a/apps/sample/trimesh_allocate/trimesh_allocate.cpp b/apps/sample/trimesh_allocate/trimesh_allocate.cpp
index 428cee49..532b12f5 100644
--- a/apps/sample/trimesh_allocate/trimesh_allocate.cpp
+++ b/apps/sample/trimesh_allocate/trimesh_allocate.cpp
@@ -49,7 +49,7 @@ int main()
   MyMesh::VertexIterator vi = vcg::tri::Allocator<MyMesh>::AddVertices(m,3);
   MyMesh::FaceIterator fi = vcg::tri::Allocator<MyMesh>::AddFaces(m,1);
 
-  MyMesh::VertexPointer ivp[3];
+  MyMesh::VertexPointer ivp[4];
   ivp[0]=&*vi; vi->P()=MyMesh::CoordType ( 0.0, 0.0, 0.0); ++vi;
   ivp[1]=&*vi; vi->P()=MyMesh::CoordType ( 1.0, 0.0, 0.0); ++vi;
   ivp[2]=&*vi; vi->P()=MyMesh::CoordType ( 0.0, 1.0, 0.0); ++vi;
@@ -58,6 +58,12 @@ int main()
   fi->V(1)=ivp[1];
   fi->V(2)=ivp[2];
 
+  // Alternative, more compact, method for adding a single vertex
+  ivp[3]=vcg::tri::Allocator<MyMesh>::AddVertex(m,MyMesh::CoordType ( 1.0, 1.0, 0.0));
+
+  // Alternative, more compact, method for adding a single face (once you have the vertex pointers)
+  vcg::tri::Allocator<MyMesh>::AddFace(m, ivp[1],ivp[0],ivp[3]);
+
   // a potentially dangerous pointer to a mesh element
   MyMesh::FacePointer fp = &m.face[0];
   vcg::tri::Allocator<MyMesh>::PointerUpdater<MyMesh::FacePointer> pu;
@@ -96,6 +102,9 @@ int main()
   vcg::tri::Allocator<MyMesh>::CompactFaceVector(m);
   vcg::tri::Allocator<MyMesh>::CompactVertexVector(m);
 
+  // To clean all the containers from deleted elements
+  vcg::tri::Allocator<MyMesh>::CompactEveryVector(m);
+
   // finally lets copy this mesh onto another one.
   MyMesh m2;
   vcg::tri::Append<MyMesh,MyMesh>::MeshCopy(m2,m);
diff --git a/apps/sample/trimesh_base/trimesh_base.cpp b/apps/sample/trimesh_base/trimesh_base.cpp
index 0c8cae7f..9f879b94 100644
--- a/apps/sample/trimesh_base/trimesh_base.cpp
+++ b/apps/sample/trimesh_base/trimesh_base.cpp
@@ -68,6 +68,7 @@ int main( int argc, char **argv )
     exit(0);
   }
 
+  vcg::tri::RequirePerVertexNormal(m);
   vcg::tri::UpdateNormal<MyMesh>::PerVertexNormalized(m);
   printf("Input mesh  vn:%i fn:%i\n",m.VN(),m.FN());
   printf( "Mesh has %i vert and %i faces\n", m.VN(), m.FN() );