Wheels are fitted to {TAIL ~ an outer end} of the piston rod of {HEAD ~ the cylinder} to prop up the propped block 
Wheels are fitted to { TAIL ~ an outer end } of the piston rod of { HEAD ~ the cylinder } to prop up the propped block
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH