{HEAD ~ The cam portion} has {TAIL ~ a cam surface} that undulates from one side of the cam plane to the other 
has
{ HEAD ~ The cam portion } has { TAIL ~ a cam surface } that undulates from one side of the cam plane to the other
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH