Subsequently, {HEAD ~ the grinding wheel} sequentially grinds {TAIL ~ the remaining object portions} while the first wheel head is returning to its home position 
sequentially grinds
Subsequently , { HEAD ~ the grinding wheel } sequentially grinds { TAIL ~ the remaining object portions } while the first wheel head is returning to its home position
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH