The first and the second blocks are formed in a center area of {HEAD ~ the tread surface} between {TAIL ~ the two third main grooves} 
between
The first and the second blocks are formed in a center area of { HEAD ~ the tread surface } between { TAIL ~ the two third main grooves }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL