anchor.diff:    override o.OnUnload(e) =
       GL.BindBuffer(BufferTarget.ArrayBuffer, 0)
       GL.DeleteBuffer(vbo)
  +    GL.DeleteBuffer(normals)
       GL.DeleteBuffer(indices)
   
       GL.UseProgram(0)
  
positive.code: 
    do base.VSync <- VSyncMode.On
  
    let positionData = [|Vector3(-1.0f, -1.0f,  1.0f);
                        Vector3( 1.0f, -1.0f,  1.0f);
                        Vector3( 1.0f,  1.0f,  1.0f);
                        Vector3(-1.0f,  1.0f,  1.0f);
                        Vector3(-1.0f, -1.0f, -1.0f);
                        Vector3( 1.0f, -1.0f, -1.0f);
                        Vector3( 1.0f,  1.0f, -1.0f);
                        Vector3(-1.0f,  1.0f, -1.0f)|]
    let indicesData = [|
                       // front face
                       0; 1; 2; 2; 3; 0;
                       // top face
                       3; 2; 6; 6; 7; 3;
                       // back face
                       7; 6; 5; 5; 4; 7;
                       // left face
                       4; 0; 3; 3; 7; 4;
                       // bottom face
                       0; 1; 5; 5; 4; 0;
                       // right face
                       1; 5; 6; 6; 2; 1; |]
    let normalData = [| Vector3(-1.0f, -1.0f,  1.0f);
                      Vector3( 1.0f, -1.0f,  1.0f);
                      Vector3( 1.0f,  1.0f,  1.0f);
  
negative.code:     GL.Clear(ClearBufferMask.ColorBufferBit ||| ClearBufferMask.DepthBufferBit)
  
      time <- time + (float32)e.Time;
      let mutable lookat = Matrix4.RotateX(time) * Matrix4.RotateY(time) * Matrix4.LookAt(Vector3(0.0f, 0.0f, -4.0f), Vector3.Zero, Vector3.UnitY)
      GL.UniformMatrix4(modelViewLocation, false, &lookat)
  
      GL.DrawElements(BeginMode.Quads, indicesData.Length, DrawElementsType.UnsignedInt, 0)
  
      GL.Flush()
      base.SwapBuffers()
  