# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'simple.8.png'
set key left below Right noreverse noinvert enhanced box linetype -1 linewidth 1.000 samplen 4 spacing 1 width 0 height 0 autotitles
set samples 800, 800
plot [-19:19] '1.dat'with impulses ,'2.dat' ,'3.dat' with lines