TikZ example

LWR.tex

\documentclass[dvipdfmx, tikz, margin=10pt]{standalone}    
\usepackage{tikz}  
\begin{document}
\begin{tikzpicture}  
\draw[step=1cm, color = gray] (0, 0) grid (3, 3);
\foreach \x  in {0, 1, 2}
{
\draw [->, thick](\x + 0.5 ,  2 + 0.5) -- (\x + 1.5 - 0.1, 2  - 0.5 + 0.1);
}
\foreach \x  in {0, 1, 2}
{
\draw [->, thick](\x + 0.5 ,  2 + 0.5) -- (\x + 0.5,  2 - 0.5 + 0.1);
}
\foreach \x  in {0, 1, 2}
{
\draw [->, thick](\x + 0.5 ,  1 + 0.5) -- (\x + 1.5 - 0.1, 1  - 0.5 + 0.1);
}
\foreach \x  in {0, 1, 2}
{
\draw [->, thick](\x + 0.5 ,  1 + 0.5) -- (\x + 0.5, 1  - 0.5 + 0.1);
}
\draw  [->,thick] (0, 3.3) -- (3.3, 3.3) node [right]{position};
\draw [->,thick] (-0.2, 3.3) -- (-0.2,-0.3) node [below]{time};
\end{tikzpicture}  
\end{document}