{HEAD ~ The first component} has {TAIL ~ an exterior first surface}, and the second component has an exterior second surface 
{ HEAD ~ The first component } has { TAIL ~ an exterior first surface } , and the second component has an exterior second surface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH