{TAIL ~ The panel} of substrate material 18 has a surface 19 and {HEAD ~ a thickness t} 
{ TAIL ~ The panel } of substrate material 18 has a surface 19 and { HEAD ~ a thickness t }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD