tikz 作图之 fill 的特性

http://bbs.pep.com.cn/thread-2283493-1-1.html

\begin{tikzpicture}[draw=red,line width=1.5pt]
\draw[fill=white] (0,0) circle (6);
\draw[fill=black] (0,-6) arc (-90:90:4) (0,2) arc (-90:-270:2) (0,6) arc (90:-90:6);
\draw[fill=gray] (0,-6) arc (-90:90:2) (0,-2) arc (-90:-270:4) (0,6) arc (90:270:2) (0,2) arc (90:-90:4);
\end{tikzpicture}

\begin{tikzpicture}
\draw[fill=white] (0,0) circle (6);
\fill[black] (0,-6) arc (-90:90:4) (0,2) arc (-90:-270:2) (0,6) arc (90:-90:6);
\fill[gray] (0,-6) arc (-90:90:2) (0,-2) arc (-90:-270:4) (0,6) arc (90:270:2) (0,2) arc (90:-90:4);
\end{tikzpicture}

啥时候 MathJax 支持 TikZ 就爽了