shifting {TAIL ~ the contents} of said plurality of memory locations 2N+1 to 1 to {HEAD ~ respective ones} of memory locations 2N to 0 
shifting { TAIL ~ the contents } of said plurality of memory locations 2N+1 to 1 to { HEAD ~ respective ones } of memory locations 2N to 0
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH