{TAIL ~ a plurality} of window system processing means, one of which can refresh a graphic display by producing {HEAD ~ graphic display data} based on original data for the graphic display 
{ TAIL ~ a plurality } of window system processing means , one of which can refresh a graphic display by producing { HEAD ~ graphic display data } based on original data for the graphic display
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH