{HEAD ~ A piston} coupled to a piston rod is fitted in {TAIL ~ a sealed cylinder} in which oil is contained 
{ HEAD ~ A piston } coupled to a piston rod is fitted in { TAIL ~ a sealed cylinder } in which oil is contained
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH