A method 1, characterized in that the pattern of {HEAD ~ openings} in the planar element is obtained by stamping {TAIL ~ the openings} in the planar element 
A method 1 , characterized in that the pattern of { HEAD ~ openings } in the planar element is obtained by stamping { TAIL ~ the openings } in the planar element
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH