such that decoding {HEAD ~ the second coded portion} relies on {TAIL ~ an output} from decoding the first coded portion; and 
relies on
such that decoding { HEAD ~ the second coded portion } relies on { TAIL ~ an output } from decoding the first coded portion ; and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH