答案1
您可以使用knots
图书馆。
\documentclass[tikz,border=3mm]{standalone}
\usetikzlibrary{knots}
\begin{document}
\begin{tikzpicture}[fat line/.style={black, double=#1,double
distance=6pt,looseness=1.2,line cap=round}]
\begin{knot}[%draft mode = crossings, % uncomment to see where the crossings are
clip width = 0,
flip crossing = 2]
\strand[fat line=gray]
(0,0) to[out=20,in=180] (2,-1) to[out=0,in=160] (4,0);
\strand[fat line=white]
(0,-1) to[out=-20,in=180] (2,0) to[out=0,in=200] (4,-1);
\end{knot}
\end{tikzpicture}
\end{document}