\documentclass[tikz]{standalone}
\usepackage{etoolbox}
\usetikzlibrary{calc}

\begin{document}

\begin{tikzpicture}[
    x=9mm,
    y=9mm,
    line cap=round,
    line join=round
]

\input{figure_base.tex}

\GrassField{10}{6}

\CornerFence{3}{5}{NE}
\CornerFence{5}{5}{NE}
\CornerFence{7}{5}{NE}

\CornerFence{1}{3}{SW}
\CornerFence{9}{3}{SE}

\CornerFence{3}{1}{SE}
\CornerFence{5}{1}{SE}
\CornerFence{7}{1}{SE}

\CornerFence[blue]{5}{3}{NW}

\GrassCell{2}{2}{20}
\GrassCell{3}{2}{20}
\GrassCell{2}{3}{20}
\GrassCell{3}{3}{20}
\GrassCell{4}{3}{20}

\GrassCell{6}{2}{20}
\GrassCell{7}{2}{20}
\GrassCell{6}{3}{20}
\GrassCell{7}{3}{20}

\end{tikzpicture}

\end{document}