Based on the value of the corresponding payload bit, the embedder will replace the original block of bits with the block of bits corresponding to one or {HEAD ~ the other alternative block} of {TAIL ~ bits} 
of
Based on the value of the corresponding payload bit , the embedder will replace the original block of bits with the block of bits corresponding to one or { HEAD ~ the other alternative block } of { TAIL ~ bits }
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 REL TAIL TAIL TAIL TAIL TAIL