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