@u26254 有一个2023年才出现的子库tikz-nfold
: https://ctan.org/ctan-ann/pkg/tikz-nfold
\documentclass[tikz,border=5pt]{standalone}
\usetikzlibrary{nfold}
\begin{document}
\tikz\draw[double,teal] (0,0) rectangle (1,1);
\tikz\draw[double distance=1pt,nfold=3,violet] (0,0) rectangle (1,1);
\tikz\draw[line join=round, double distance=4pt, nfold=4, magenta] (0,0) rectangle (1,1);
\end{document}
问 tikz 如何绘制三线路径