{HEAD ~ The stems} 112 slide freely between {TAIL ~ fully extended positions} as shown in FIG 3 and fully withdrawn positions as shown in FIG 4 
slide freely between
{ HEAD ~ The stems } 112 slide freely between { TAIL ~ fully extended positions } as shown in FIG 3 and fully withdrawn positions as shown in FIG 4
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH