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