More preferably, each of {TAIL ~ the tags} includes first identity data defining a relative position of {HEAD ~ that tag}, and second identity data identifying the surface 
More preferably , each of { TAIL ~ the tags } includes first identity data defining a relative position of { HEAD ~ that tag } , and second identity data identifying the surface
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH