set parametric
set trange [0:2*pi]
set size ratio -1
unset key 
set samples 200
set title "lissajous" font "Times,20" 
set term pngcairo enh font "Helvetica,10" size 480,360
set out "2dparam_lissajous.png"
plot cos(t), sin(t), cos(t), sin(3*t)