# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'surface1.1.png'
set label 1 "This is the surface boundary" at -10, -5, 150 centre norotate back nopoint
set arrow 1 from -10, -5, 120 to -10, 0, 0  nohead back nofilled linetype 1 linewidth 1.000
set arrow 2 from -10, -5, 120 to 10, 0, 0  nohead back nofilled linetype 1 linewidth 1.000
set arrow 3 from -10, -5, 120 to 0, 10, 0  nohead back nofilled linetype 1 linewidth 1.000
set arrow 4 from -10, -5, 120 to 0, -10, 0  nohead back nofilled linetype 1 linewidth 1.000
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