\documentclass{standalone}

\usepackage{tikz}
\usepackage{dimer}

\begin{document}
\begin{tikzpicture}

\fill[color=gray](1,0.5)--++(1,0)--++(0.5,0.5)--++(-0.5,0.5)--++(-1,0)--++(-0.5,-0.5)--cycle;
\draw[line width=15pt,color=gray](1,-2.5)--(1,1);
\grid{3}{5}{[color=lightgray](0,-3)}
\draw[color=black, line width=5pt](1,0.5)--++(1,0)--++(0.5,0.5)--++(-0.5,0.5)--++(-1,0)--++(-0.5,-0.5)--cycle;

\end{tikzpicture}
\end{document}