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