{HEAD ~ The first main groove} is made of {TAIL ~ a see through groove} extending in the tire circumferential direction 
{ HEAD ~ The first main groove } is made of { TAIL ~ a see through groove } extending in the tire circumferential direction
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH