{TAIL ~ 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 the block 
{ TAIL ~ 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 the block
TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH