\draw (-2,1.5) rectangle (2,-1.5);
\begin{scope}
\clip (-0.5,0) circle (1);
\clip (0.5,0) circle (1);
\fill[color=gray] (-2,1.5) rectangle (2,-1.5);
\end{scope}
\draw (-0.5,0) circle (1);
\draw (0.5,0) circle (1);
