and indicate the position directed by {HEAD ~ the contents} of {TAIL ~ the IMA counter} to represent the position of the present cursor 
and indicate the position directed by { HEAD ~ the contents } of { TAIL ~ the IMA counter } to represent the position of the present cursor
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH