Alternatively, the data can be stored in fixed locations and {HEAD ~ the portals} moved from {TAIL ~ location} to location 
moved from
Alternatively , the data can be stored in fixed locations and { HEAD ~ the portals } moved from { TAIL ~ location } to location
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH