# set terminal pngcairo  background "#ffffff" enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'pm3d.24.png'
set border 895 front linetype -1 linewidth 1.000
set tics back
set grid nopolar
set grid xtics nomxtics ytics nomytics noztics nomztics \
 nox2tics nomx2tics noy2tics nomy2tics nocbtics nomcbtics
set grid back   linetype 0 linewidth 1.000,  linetype 0 linewidth 1.000
set style line 100  linetype 5 linecolor rgb "#f0e442"  linewidth 0.500 pointtype 5 pointsize default pointinterval 0
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 nomcbtics
set title "using now \"set grid back; unset colorbox\"" 
set pm3d implicit at s
unset colorbox
splot y