diff --git a/src/array.h b/src/array.h
index e7bd5b10..57a7fa90 100644
--- a/src/array.h
+++ b/src/array.h
@@ -40,7 +40,7 @@ public:
         return m_data[n];
     }
 
-    inline Array<T1, T2, T3> const& operator+=(Element const &x)
+    inline Array<T1, T2, T3> const& operator<<(Element const &x)
     {
         if (m_count >= m_reserved)
         {
@@ -127,7 +127,7 @@ public:
         return m_data[n];
     }
 
-    inline Array<T1, T2> const& operator+=(Element const &x)
+    inline Array<T1, T2> const& operator<<(Element const &x)
     {
         if (m_count >= m_reserved)
         {
@@ -210,7 +210,7 @@ public:
         return m_data[n];
     }
 
-    inline Array<T1> const& operator+=(T1 const &x)
+    inline Array<T1> const& operator<<(T1 const &x)
     {
         if (m_count >= m_reserved)
         {
@@ -227,7 +227,7 @@ public:
 
     inline void Append(T1 const &x)
     {
-        *this += x;
+        *this << x;
     }
 
     void Remove(int pos)
diff --git a/test/tutorial/01_triangle.cpp b/test/tutorial/01_triangle.cpp
index 1f342f59..bb6e3bbe 100644
--- a/test/tutorial/01_triangle.cpp
+++ b/test/tutorial/01_triangle.cpp
@@ -36,9 +36,9 @@ class Triangle : public WorldEntity
 public:
     Triangle()
     {
-        m_vertices += vec2( 0.0,  0.8);
-        m_vertices += vec2(-0.8, -0.8);
-        m_vertices += vec2( 0.8, -0.8);
+        m_vertices << vec2( 0.0,  0.8);
+        m_vertices << vec2(-0.8, -0.8);
+        m_vertices << vec2( 0.8, -0.8);
         m_ready = false;
     }
 
diff --git a/test/tutorial/02_cube.cpp b/test/tutorial/02_cube.cpp
index be691e6c..2c55bbd9 100644
--- a/test/tutorial/02_cube.cpp
+++ b/test/tutorial/02_cube.cpp
@@ -45,18 +45,18 @@ public:
         m_mesh.Append(vec3( 1.0,  1.0, -1.0), vec3(0.0, 0.5, 1.0));
         m_mesh.Append(vec3(-1.0,  1.0, -1.0), vec3(0.0, 0.0, 1.0));
 
-        m_indices += i16vec3(0, 1, 2);
-        m_indices += i16vec3(2, 3, 0);
-        m_indices += i16vec3(1, 5, 6);
-        m_indices += i16vec3(6, 2, 1);
-        m_indices += i16vec3(7, 6, 5);
-        m_indices += i16vec3(5, 4, 7);
-        m_indices += i16vec3(4, 0, 3);
-        m_indices += i16vec3(3, 7, 4);
-        m_indices += i16vec3(4, 5, 1);
-        m_indices += i16vec3(1, 0, 4);
-        m_indices += i16vec3(3, 2, 6);
-        m_indices += i16vec3(6, 7, 3);
+        m_indices << i16vec3(0, 1, 2);
+        m_indices << i16vec3(2, 3, 0);
+        m_indices << i16vec3(1, 5, 6);
+        m_indices << i16vec3(6, 2, 1);
+        m_indices << i16vec3(7, 6, 5);
+        m_indices << i16vec3(5, 4, 7);
+        m_indices << i16vec3(4, 0, 3);
+        m_indices << i16vec3(3, 7, 4);
+        m_indices << i16vec3(4, 5, 1);
+        m_indices << i16vec3(1, 0, 4);
+        m_indices << i16vec3(3, 2, 6);
+        m_indices << i16vec3(6, 7, 3);
 
         m_ready = false;
     }