/draw_arc { % x y => - (draws an arc at the specifed location)
      100 0 300 arc			% locate the arc
      gsave			% save the context
          .5 setgray fill			% fill path with gray
      grestore			% restore context
      stroke			% draw the arc
} def

/makewin { %  - => - (builds a test window)
      /GoWindow DefaultWindow			% create a subclass
      dictbegin				% begin local dict
           /FrameLabel ( Workspace ) def
      dictend				% end local dict
      classbegin			% begin class defs
           /PaintClient { 100 100 draw_arc } def		% draw gray arc
           /PaintIcon {			% drawing icon image
                       .5 fillcanvas			% fill with gray
                       0 strokecanvas			% stroke the perimeter
           } def  
       classend def			% end class definition

       /win framebuffer /new GoWindow send def		% cliche
       /reshapefromuser win send			% resize window
       /map win send			% make it visible
} def

makewin			% run the program