The three GLUT functions glutWindowPosition, glutWindowSize and glutCreateWindow establish for us the window used in displaying the graphical content created with OpenGL. The two integer parameters to glutWindowPosition define the location on the screen of the upper-left corner of our window, while the two integer parameters to lutWindowSize establish, respectively, the width and height of the desired window. The width and height do not include the window borders but give the width and height of the interior area, sometimes called the client area of the window. The call to glutCreateWindow is the GLUT function that causes the window to be created. The function requires one string parameter, which becomes the banner displayed in the top border of the window. For example, the three calls given here creates a window in the upper-left corner of the screen that has a client area of 500 by 500 pixels and the banner "Hello (Line Loop) World".