\documentclass{standalone}

\usepackage{tikz}
\usepackage{dimer}

\begin{document}
\begin{tikzpicture}

\fill[color=gray](2,0.5)--++(3,0)--++(1.5,1.5)--++(-1.5,1.5)--++(-3,0)--++(-1.5,-1.5)--cycle;
\fill[color=white](3,1.5)--++(1,0)--++(0.5,0.5)--++(-0.5,0.5)--++(-1,0)--++(-0.5,-0.5)--cycle;
\grid{7}{4}{[color=lightgray](0,0)}
\draw[color=black, line width=5pt](2,0.5)--++(3,0)--++(1.5,1.5)--++(-1.5,1.5)--++(-3,0)--++(-1.5,-1.5)--cycle;

\end{tikzpicture}
\end{document}