In accordance with {TAIL ~ the invention}, discrete areas of {HEAD ~ the screen} are formed or treated so as to restrict drainage through those areas compared to the drainage through adjacent untreated areas 
In accordance with { TAIL ~ the invention } , discrete areas of { HEAD ~ the screen } are formed or treated so as to restrict drainage through those areas compared to the drainage through adjacent untreated areas
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH