{HEAD ~ The percent area A} of {TAIL ~ the plane} in the slide surface is set in a range of A≧50% 
{ HEAD ~ The percent area A } of { TAIL ~ the plane } in the slide surface is set in a range of A≧50 %
HEAD HEAD 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