In preferred embodiments, the pitch between corrugations may be five inches, with {HEAD ~ a depth} of {TAIL ~ one half inch} 
of
In preferred embodiments , the pitch between corrugations may be five inches , with { HEAD ~ a depth } of { TAIL ~ one half inch }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL