弯曲线条使其更美观？

Question

如何像第一张图片那样弯曲线条并且更美观。谢谢我想将字母“l”和“d”组合在一起。

\documentclass[tikz,border=1pt]{standalone}
\usetikzlibrary{arrows,scopes}
\begin{document}
\begin{tikzpicture}
\fill[green, even odd rule] (0,0) circle[radius=6] (0,0) circle[radius=4];
\draw [line width=2cm, green,line cap=round] (5,12) --  (5,0);
\draw [line width=2cm, green,line cap=round] (-5,12) --  (-5,0);
\end{tikzpicture}
\end{document}

Answer 1

\documentclass[tikz,border=1pt]{standalone}
\begin{document}
\begin{tikzpicture}
\fill[green, even odd rule] (0,0) circle[radius=6] (0,0) circle[radius=4];
\draw [line width=2cm, green,line cap=round] (5,0) -- (5,4) to[out=90, in=0] (1.5,10);
\draw [line width=2cm, green,line cap=round] (-5,0) -- (-5,4) to[out=90, in=180] (-1.5,10);
\end{tikzpicture}
\end{document}