This creates {TAIL ~ a pressure difference} between the cells causing {HEAD ~ the vent follower} to move until it arrives at an equilibrium position 
This creates { TAIL ~ a pressure difference } between the cells causing { HEAD ~ the vent follower } to move until it arrives at an equilibrium position
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH