printf "${sep}"' \\'"\n" >> ${gpfile}
  printf '  (x > 2*('"${zmax}"'-'"${zref}"') ? 0/0 : '"${coef}"'*(x**'"${expt}"'))' >> ${gpfile}
  printf   ' '"${tit}" >> ${gpfile}
  printf   ' with lines linetype 0' >> ${gpfile} 
  printf   ","' \\'"\n" >> ${gpfile} 
  printf '  "'"${tpfile}"'"' >> ${gpfile} 
  printf   ' using (column(1)-'"${zref}"'):(column(0)+1)' >> ${gpfile} 
  printf   ' title "'"${seed}"'"' >> ${gpfile} 
  printf   ' with linespoints linetype '"${seed}" >> ${gpfile}