gnuplot> set xrange [-1:1] gnuplot> set yrange [-1:1] gnuplot> set zrange [-3.3:2] gnuplot> splot -x**2-y**2+x-y+y**3-x**3-y**12+x**8 gnuplot> set terminal png Terminal type set to 'png' Options are 'small color picsize 640 480 ' gnuplot> set output "gnu.png" gnuplot> replot