BigClock()

         Shows a digital watch tich large numbers

    Syntax:

         BigClock( [nRow], [nCol] ) -> Nil

         nRow   : Row position
         nCol   : Column position

    Description:

         This function shows a digital watch with large numbers and waits
         until a key is pressed restoring the screen.

    Return:

         Nothing.

    Example:

         BigClock( 10, 20 )