答案1
简单even odd rule
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\fill[cyan] (-3,-3) rectangle (3,3);
\draw[fill=red,even odd rule] (-1,0) circle (1.5cm) (1,0) circle (1.5cm);
\end{tikzpicture}
\begin{tikzpicture}
\fill[cyan] (-3,-3) rectangle (3,3);
\draw[fill=red,even odd rule] (-1,0) circle (1.5cm) (1,0) circle (1.5cm) (0,-1) circle(1.5cm);
\end{tikzpicture}
\end{document}