At a second position, in which the stem is withdrawn by {HEAD ~ one step} from {TAIL ~ the most inserted first position}, the stem is allowed to turn in both the right and left directions by a suitable angle 
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At a second position , in which the stem is withdrawn by { HEAD ~ one step } from { TAIL ~ the most inserted first position } , the stem is allowed to turn in both the right and left directions by a suitable angle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH