{HEAD ~ A relative positioning system} enabling a user to return to a starting position or {TAIL ~ some other point} on the users path 
{ HEAD ~ A relative positioning system } enabling a user to return to a starting position or { TAIL ~ some other point } on the users path
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH