For a block that may be designated for implementation in either software or hardware, the block may have a specification in block specifications 504 that is either a specification in {HEAD ~ a general purpose programming language} or a specification in {TAIL ~ a hardware description language} 
For a block that may be designated for implementation in either software or hardware , the block may have a specification in block specifications 504 that is either a specification in { HEAD ~ a general purpose programming language } or a specification in { TAIL ~ a hardware description language }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL