public void Paint(object sender, PaintEventArgs e)
        {
            if (null == sender)
            {
                return;
            }
            if (false == (sender is GRControl))
            {
                return;
            }

            GRControl grControl = (sender as GRControl);
            GR        gr        = grControl.GetGR( );

            int clientWidth  = grControl.ClientRectangle.Width;
            int clientHeight = grControl.ClientRectangle.Height;

            if (clientWidth <= 0)
            {
                clientWidth = 1;
            }
            if (clientHeight <= 0)
            {
                clientHeight = 1;
            }


            // Viewport
            gr.glViewport(0, 0, clientWidth, clientHeight);


            // Clear the viewport
            gr.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
            gr.glClear(GR.GL_COLOR_BUFFER_BIT | GR.GL_DEPTH_BUFFER_BIT);


            // Basic rendering conditions
            gr.glEnable(GR.GL_DEPTH_TEST);
            gr.glDepthFunc(GR.GL_LEQUAL);
            gr.glEnable(GR.GL_CULL_FACE);
            gr.glCullFace(GR.GL_BACK);
            gr.glFrontFace(GR.GL_CCW);



            gr.glMatrixMode(GR.GL_PROJECTION);
            gr.glLoadIdentity( );
            gr.gluOrtho2D(0.0, (double)clientWidth, 0.0, (double)clientHeight);

            gr.glMatrixMode(GR.GL_MODELVIEW);
            gr.glLoadIdentity( );



            // TETRIS GAME ITERATION

            STUserInterface.PerformGameIterations
            (
                STEngine.GetGame( ),
                grControl.GetPreviousFrameDurationSeconds( )
            );


            // TETRIS GAME DRAWING

            System.Drawing.Point controlRelativePoint = grControl.PointToClient(Cursor.Position);
            int clientRelativeCursorX = controlRelativePoint.X;
            int clientRelativeCursorY = controlRelativePoint.Y;

            STGameDrawing.DrawScreen
            (
                clientWidth,
                clientHeight,
                clientRelativeCursorX,
                clientRelativeCursorY,
                gr,
                STEngine.GetGame( ),
                STEngine.GetConsole( )
            );



            // Flush all the current rendering and flip the back buffer to the front.
            gr.wglSwapBuffers(grControl.GetHDC( ));
        }