elem-grid_RBG_draw_boxes+elem+foreach+style.tex

% arr: add comments, indent code
%	change cell color to gray

\documentclass[tikz,border=10pt]{standalone}
%\documentclass[crop, tikz]{standalone}

\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
	[%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	box/.style={rectangle, draw=black, thick, minimum size=1cm, fill=gray!10},
	]%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	
	% draw boxes based on (x,y) coordinates
	\foreach \x in {0,1,...,10} {
		\foreach \y in {0,1,...,10}   
			\node[box] at (\x, \y) {}; 
	}
	
	\node[box, fill=green] at (8,8){};  
	\node[box, fill=red  ] at (5,5){};  
	\node[box, fill=blue ] at (2,2){};  

\end{tikzpicture}

\end{document}