English: A Lissajous curve that can be expressed in parametric form as:

${\displaystyle x=A\sin(at+\delta ),\quad y=B\sin(bt)}$

with ${\displaystyle a=7}$, ${\displaystyle b=6}$ and ${\displaystyle \delta =\pi /2}$. I created it with the following GNUplot code:

set samples 5000
set terminal svg
set output "Lissajous_curve_1by2.svg"

# plotting within a square
set size square

# remove most of information from the picture
unset xtic
unset ytic
set key off

# plot
set parametric
a=7
b=6
delta=pi/2
plot [0:pi/2] sin(a*t + delta),sin(b*t) with lines linewidth 2

and then I post-processed with Inkscape: I converted the graph to beziers (aka Simplify), cloned and rotated the curve (π/2) to get the entire graph (2π), and resized the final image to 600x600 with a 18.854px margin, like the others. I also manually edited and removed any unnecessary elements. All of this resulted in a smoother graph with a small file size.