リサジュー曲線
Lissajous curve
code:jl
using Plots
θ = 0:0.01:2π # \theta
δ = 0
x = cos.(4θ)
y = sin.(5θ .+ δ)
plot(x, y; framestyle=:origin, ratio=:equal)
https://youtu.be/6i-Hva8gv8E