a second series of {TAIL ~ laser drilled wells}, having a second spacing are made in {HEAD ~ the substrate material} to form the remaining portion of the perimeter of the irregular shaped substrate 
a second series of { TAIL ~ laser drilled wells } , having a second spacing are made in { HEAD ~ the substrate material } to form the remaining portion of the perimeter of the irregular shaped substrate
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH