The eccentrics are out of phase with each other corresponding to the out of phase between {HEAD ~ pair} of {TAIL ~ cranks} 
of
The eccentrics are out of phase with each other corresponding to the out of phase between { HEAD ~ pair } of { TAIL ~ cranks }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL