\documentclass[a4paper,12pt]{report}
\usepackage{tikz}
\usepackage{xepersian}
\usetikzlibrary{arrows}
\settextfont[Scale=1.1]{XB Zar}
\setdigitfont{Yas}
\pagestyle{plain}
\begin{document}
   \begin{center}
\begin{tikzpicture}[
    scale=1,
    axis/.style={very thick, ->, >=stealth'},
    important line/.style={thick},
    dashed line/.style={dashed, thin},
    pile/.style={thick, ->, >=stealth', shorten <=2pt, shorten
    >=2pt},
    every node/.style={color=black}
    ]\label{total}
    %grid
\draw[color=gray] (-1,-1) grid (6,6);
% p-q axis
   \draw[axis] (-1,0)  -- (6,0) node(xline)[right]{$p$};
    \draw[axis] (0,-1) -- (0,6) node(yline)[above] {$q$};
    %line n=p+q
  \draw[color=black] (6,-1) -- (-1,6);
  %red points
  \fill[red] (6,-1) circle (2pt);
   \fill[red] (5,0) circle (2pt);
   \fill[red] (4,1) circle (2pt);
    \fill[red] (3,2) circle (2pt);
      \fill[red] (2,3) circle (2pt);
       \fill[red] (1,4) circle (2pt);
         \fill[red] (0,5) circle (2pt);
         \fill[red] (6,-1) circle (2pt) node[below right]{$n=p+q$};
         %line n-1=p+q
    \draw[color=black] (5,-1) -- (-1,5);
    %red point
    \fill[red] (5,-1) circle (2pt)node[below left]{$n-1=p+q$};
     \fill[red] (4,0) circle (2pt);
    \fill[red] (3,1) circle (2pt);
     \fill[red] (2,2) circle (2pt);
      \fill[red] (1,3) circle (2pt);
       \fill[red] (0,4) circle (2pt);
       \fill[red] (-1,5) circle (2pt);
   %flesh
      \draw[pile] (5,0) -- (5,-1) ;
      \draw[pile] (5,0) -- (4,0) ;
      \draw[pile] (4,1) -- (4,0) ;
      \draw[pile] (4,1) -- (3,1);
      \draw[pile] (3,2) -- (3,1) ;
      \draw[pile] (3,2) -- (2,2);
      \draw[pile] (2,3) -- (2,2) ;
      \draw[pile] (2,3) -- (1,3);
      \draw[pile] (1,4) -- (1,3) ;
      \draw[pile] (1,4) -- (0,4);
      \draw[pile] (0,5) -- (0,4) ;
      \draw[pile] (0,5) -- (-1,5);
              \end{tikzpicture}
\end{center}
\end{document}