How to draw something like a spiral in TikZ?

Question

I need to draw something like a spiral which is shown in the picture below. The most important thing for me is this kind of spiral, because two rings are easy to draw. Could you help me with this?

Answer 1

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
  \draw[thick] circle (1) circle (3);
  \draw[domain=0:725,samples=50,smooth,line width=3mm,gray!50]
    plot (\x:{2+0.5*sin(0.5*(\x-45))});
\end{tikzpicture}
\end{document}

In the formula 2+0.5*sin(0.5*(\x-45)) you can adjust the following values: The value 2 is the distance from the center where the braid intersects with itself. The first 0.5 is the maximal distance that the braid moves away from the circle with radius 2; here it oscillates between 2-0.5=1.5 and 2+0.5=2.5. Finally, the number 45 is the angle at which the braid intersects with itself. The width of the braid is currently 3mm, determined by the option line width=3mm.