# set terminal pngcairo  background "#ffffff" enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'pm3d.21.png'
set border 4095 front linetype -1 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 ticslevel 0
set title "color box is on by default at a certain position" 
set pm3d implicit at s
splot y