Therefore a swimmer can see {HEAD ~ the display} of {TAIL ~ the signal lamps} 3 while standing on the starting block 4 
of
Therefore a swimmer can see { HEAD ~ the display } of { TAIL ~ the signal lamps } 3 while standing on the starting block 4
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