# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'surface1.9.png'
set style increment default
set samples 21, 21
set isosamples 11, 11
set style data lines
set title "3D gnuplot demo" 
set xlabel "X axis" 
set xlabel  offset character -3, -2, 0 font "" textcolor lt -1 norotate
set xrange [ -10.0000 : 10.0000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set ylabel "Y axis" 
set ylabel  offset character 3, -2, 0 font "" textcolor lt -1 rotate
set yrange [ -10.0000 : 10.0000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zlabel "Z axis" 
set zlabel  offset character -5, 0, 0 font "" textcolor lt -1 norotate
set zrange [ * : * ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
## Last datafile plotted: "$grid"
splot x*y with points