\documentclass[12pt]{standalone}
\pagestyle{empty}
\usepackage{tikz}
\definecolor{darkblue}{rgb}{0,0,.7}
\begin{document}

\begin{tikzpicture}

\begin{scope}
\clip (0,0)--(9,0)--(7,4)--(-2.5,4);
\fill[yellow] (-1,0)--(2,3)--(8,0);
\foreach \x in {-4,-3,-2,-1,0,1,2,3,4,5,6,7, 8} \draw [red] (\x,0)--(\x+3,3);
\foreach \x in {-4,-3,-2,-1,0,1,2,3,4,5,6,7, 8} \draw [cyan] (\x,0)--(\x-3,3);
\foreach \x in {-4,-3,-2,-1,0,1,2,3,4,5,6,7, 8} \draw [blue] (\x+3,0)--(\x-3,3);

\fill (2,3) circle (.05) node[above] {$P$};
\node at (3,1) {\colorbox{white}{$\Delta(P)$}};
\end{scope}

\draw[thin] (-2,0)--(0,0);
\draw[very thick,->] (0,0)--(8.5,0) node[below]{$x$};
\draw[very thick,->] (0,0)--(-2,3);
\node at (-1,1) {$\Gamma$};

\end{tikzpicture}
\end{document}
