BackGraph()

         Draws the back of the 3D graphic

    Syntax:

         BackGraph ( cTitle, nMaxValue, nBaseSize ) -> Nil

         cTitle        : The title of the graphic
         nMaxValue     : The maximum value of the graphic
         nBaseSize     : The base size in pixels

    Description:

         Draws the back of the 3D graphic including title and scale
         depending on nMaxValue.

         In this way, with this function and DrawBar() you can build
         your graphics.

    Return:

         Nothing.

    Example:

         SetVGA()
         BackGraph( "This is a demo", 150000, 60 )
         Inkey( 0 )
         TxtMode()