interaction between the cam follower and the cam curvilinear surface creating {HEAD ~ a plurality} of {TAIL ~ pushbutton equilibrium states} 
of
interaction between the cam follower and the cam curvilinear surface creating { HEAD ~ a plurality } of { TAIL ~ pushbutton equilibrium states }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL