Bridges or {TAIL ~ webs} are typically provided at {HEAD ~ different elevations} to define the cavities, which may be cored 
Bridges or { TAIL ~ webs } are typically provided at { HEAD ~ different elevations } to define the cavities , which may be cored
OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH