\documentclass{standalone}

\usepackage{tikz}
\usepackage{shapes}

\begin{document}
\begin{tikzpicture}
  \grid{7}{7}{(-1,-1)}

  \square{gray}{(1,4)}
  \square{gray}{(2,3)}
  \square{gray}{(2,4)}
  \square{gray}{(3,2)}
  \square{gray}{(3,3)}
  \square{gray}{(3,4)}
  \square{gray}{(4,1)}
  \square{gray}{(4,2)}
  \square{gray}{(4,3)}
  \square{gray}{(4,4)}
  
  \square{yellow}{(0,4)}
  \square{yellow}{(1,3)}
  \square{yellow}{(2,2)}
  \square{yellow}{(3,1)}
  \square{yellow}{(4,0)}
  
  \square{magenta}{(5,1)}
  \square{magenta}{(5,2)}
  \square{magenta}{(5,3)}
  \square{magenta}{(5,4)}

  \square{green}{(1,5)}
  \square{green}{(2,5)}
  \square{green}{(3,5)}
  \square{green}{(4,5)}

\end{tikzpicture}
\end{document}