In the meantime, the pinholes SS12, {HEAD ~ SS13} are partially overlapped with {TAIL ~ the focused target track} S11 
In the meantime , the pinholes SS12 , { HEAD ~ SS13 } are partially overlapped with { TAIL ~ the focused target track } S11
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH