It comprises a cylinder , which is closed at one end, and {HEAD ~ piston} , which slides inside {TAIL ~ the cylinder}  
It comprises a cylinder , which is closed at one end , and { HEAD ~ piston } , which slides inside { TAIL ~ the cylinder }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH