# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'pm3d.20.png'
set border 4095 front linetype -1 linewidth 1.000
set grid nopolar
set grid noxtics nomxtics noytics nomytics noztics nomztics \
 nox2tics nomx2tics noy2tics nomy2tics cbtics nomcbtics
set grid layerdefault   linetype 0 linewidth 1.000,  linetype 0 linewidth 1.000
set style line 100  linetype 5 linewidth 0.500 pointtype 100 pointsize default
set samples 20, 20
set isosamples 20, 20
unset surface
set size ratio 0 0.6,0.6
set origin 0.2,0.25
set ticslevel 0
set mcbtics 2.000000
set title "color box is on again, now with horizontal gradient" 
set xrange [ * : * ] noreverse nowriteback  # (currently [-1.00000:1.00000] )
set yrange [ * : * ] noreverse nowriteback  # (currently [-1.00000:1.00000] )
set zrange [ * : * ] noreverse nowriteback  # (currently [-15.0000:60.0000] )
set cblabel "see cblabel, grid cb, mcbtics, ..." 
set cbrange [ * : * ] noreverse nowriteback  # (currently [-15.0000:4.00000] )
set pm3d implicit at s
set colorbox user
set colorbox horizontal origin screen 0.1, 0.15, 0 size screen 0.8, 0.1, 0 bdefault
splot y