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