{HEAD ~ The routes} 4 to 9 are provided in an overhead space in {TAIL ~ a clean room} 
{ HEAD ~ The routes } 4 to 9 are provided in an overhead space in { TAIL ~ a clean room }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL