{HEAD ~ A force} modifying {TAIL ~ member rotatable} about a fixed axis is provided and includes first and second outwardly facing surfaces of predetermined lengths which curve about the axis 
modifying
{ HEAD ~ A force } modifying { TAIL ~ member rotatable } about a fixed axis is provided and includes first and second outwardly facing surfaces of predetermined lengths which curve about the axis
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH