Trefoil knot

Trefoil knot

\documentclass[border=10pt]{standalone}
\usepackage{asymptote}
\begin{document}
\begin{asy}[width=\the\linewidth,inline=true]
settings.outformat="pdf";
settings.render=0;
settings.prc=false;
import graph3;
import tube;

size(200,0);
currentlight.background=paleyellow+opacity(0.0);
currentprojection=orthographic(camera=(-40,9,70), up=Z);

real x(real t){return sin(t)+2sin(2t);}
real y(real t){return cos(t)-2cos(2t);}
real z(real t){return -sin(3t);}

guide3 g=graph(x,y,z, 0, 2pi,operator..);

draw(tube(g,circle((0,0),0.618)),white);
\end{asy}
\end{document}

Source: TeX.SE

Author: g.kov (License)