A specification of each block in a first subset is obtained from the library and translated into an execution function of {HEAD ~ the software implementation} of {TAIL ~ the block} 
A specification of each block in a first subset is obtained from the library and translated into an execution function of { HEAD ~ the software implementation } of { TAIL ~ the block }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL