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