Each of {TAIL ~ the gas supply nozzles} may branch of a single supply line connected to {HEAD ~ a single source gas supply} 
Each of { TAIL ~ the gas supply nozzles } may branch of a single supply line connected to { HEAD ~ a single source gas supply }
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD