1 FILL
  Syntax: FILL id [&idb] x y [dx [dy] ...]
      or  FILL id [&idb] x [y]
   where: id    is the plot identifier
          idb   is the (optional) secondary identifier
          x     is the x value of the point
          y     is the y value of the point
          dx    is the error on x
          dy    is the error on y etc.

  Fills a plot.  Alias for `HIST  FILL'. See HELP HISTOGRAM FILL for more
  details.

