Thus, each block may have a single specification in block specifications 504 that may be used to generate {HEAD ~ either a software or hardware implementation} of {TAIL ~ the block} 
of
Thus , each block may have a single specification in block specifications 504 that may be used to generate { HEAD ~ either a software or hardware implementation } of { TAIL ~ the block }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL