\documentclass{standalone}

\usepackage{tikz}
\usepackage{shapes}

\begin{document}
\begin{tikzpicture}
  \grid{6}{11}{(-3,-3)}

  \square{sequential4-2}{(-2,2)}
  \square{sequential4-2}{(2,2)}

  \disk{sequential4-1}{(0,0)}

  \disk{sequential4-3}{(0,5)}

\end{tikzpicture}
\end{document}