# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'surface1.8.png'
set samples 21, 21
set isosamples 11, 11
set title "3D gnuplot demo" 0.000000,0.000000  font ""
set xlabel "X axis" -3.000000,-2.000000  font ""
set xrange [ -10.0000 : 10.0000 ] noreverse nowriteback
set ylabel "Y axis" 3.000000,-2.000000  font ""
set yrange [ -10.0000 : 10.0000 ] noreverse nowriteback
set zlabel "Z axis" -5.000000,0.000000  font ""
splot x*y with points