awesome style

set terminal pngcairo

set style line 1 lw 2 pt 6 lc rgb "#00aaaa"

set style line 11 lc rgb '#808080' lt 1 lw 3
set border 0 back ls 11
set tics out nomirror

set style line 12 lc rgb '#808080' lt 0 lw 1
set grid back ls 12

set xrange [-4:4]
plot x**3

以下は pngcairo ではないが

Gnuplot Produced by GNUPLOT 5.5 patchlevel 0 -80 -60 -40 -20 0 20 40 60 80 -4 -3 -2 -1 0 1 2 3 4 x**3 x**3