Procedure Add(X1, Y1, X2, Y2:Word; Special:Boolean; Key:Char)

    This adds a button to  your  object's  linked  list.  The screen area
    X1,Y1  to   X2,Y2   is   marked   as   a   button  and  is  allocated
    space on  the  heap  (not  for  screen  data  -  just  for  the above
    information).  A key press  is  assigned  to  the button.  It is then
    allocated a unique number.  This new  button then becomes the current
    button.

    The button is  not  displayed.    A  button  may  be anything, from a
    single character to a word to  a  ASCII  drawn  button.   It is up to
    you to write your  own  button  display  program  if  you want to use
    fancy ASCII buttons.  Often  a  word  in  a special background colour
    will do as a button.

    The coordinates are specified in  characters  (that  is, (1,1) is the
    top left hand corner), not pixels.