# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'pm3d.13.png'
set border 4095 front linetype -1 linewidth 1.000
set view 130, 10, 1, 1
set samples 50, 50
set isosamples 50, 50
unset surface
set title "set pm3d scansforward: wrong, because back overwrites front" 
set pm3d implicit at s
set pm3d scansforward
splot sin(sqrt(x**2+y**2))/sqrt(x**2+y**2)