{HEAD ~ The pistons} are connected to a crankshaft via two connecting rods which are pivotally connected to {TAIL ~ the same crank pin} 
{ HEAD ~ The pistons } are connected to a crankshaft via two connecting rods which are pivotally connected to { TAIL ~ the same crank pin }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL