#Multiplot
set terminal png size 600, 400
set output 'plot.png'
set multiplot

set size 0.5 , 0.5

set origin 0,0
pl sin(x)

set origin 0,0.5 
pl x**2 w p

set origin 0.5,0
pl exp(-x**2/2) w lp

set origin 0.5,0.5
pl tan(x)