 within each rectangle portion, after dividing {TAIL ~ data blocks} into {HEAD ~ a plurality} of square portions, allocating any remaining blocks to a partial portion; and 
within each rectangle portion , after dividing { TAIL ~ data blocks } into { HEAD ~ a plurality } of square portions , allocating any remaining blocks to a partial portion ; and
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH