# set terminal svg size 600,400 dynamic enhanced fname 'arial'  fsize 10 mousing name "surface1_4" butt solid 
# set output 'surface1.4.svg'
set grid nopolar
set grid xtics nomxtics ytics nomytics noztics nomztics \
 nox2tics nomx2tics noy2tics nomy2tics nocbtics nomcbtics
set grid layerdefault   linetype 0 linewidth 1.000,  linetype 0 linewidth 1.000
set samples 21, 21
set isosamples 11, 11
set style data lines
set title "3D surface from a function" 
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 ylabel "Y axis" 
set ylabel  offset character 3, -2, 0 font "" textcolor lt -1 rotate by -270
set yrange [ -10.0000 : 10.0000 ] noreverse nowriteback
set zlabel "Z axis" 
set zlabel  offset character -5, 0, 0 font "" textcolor lt -1 norotate
x = 0.0
splot x**2+y**2, x**2-y**2, x*y