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