\documentclass[a4paper,12pt]{report} 
\usepackage{tikz,amsmath,amssymb}

\tikzstyle{vertex}=[circle, draw, inner sep=0pt, minimum size=16pt] 
\newcommand{\vertex}{\node[vertex]}
\tikzstyle{vertexs}=[draw,minimum width=.6cm,minimum height=.6cm]
\newcommand{\vertexs}{\node[vertexs]}
شکل دوتایی
\begin{figure}[htbp]
\[\begin{array}{cc}
\begin{tikzpicture}[scale=1,thick,>=stealth] 
\vertex (a1) at (0,0) []{};
\vertexs (b1) at (0,-1.5) []{};
\vertex (a2) at (-1.6,-3) []{};
\vertex (a3) at (-.8,-3) []{};
\vertex (a4) at (0,-3) []{};
\vertex (a5) at (.8,-3) []{};
\vertex (a6) at (1.6,-3) []{};
\draw [->] (b1) -- (a1);
\draw [->] (a2) -- (b1);
\draw [->] (a3) -- (b1);
\draw [->] (a4) -- (b1);
\draw [->] (a5) -- (b1);
\draw [->] (a6) -- (b1);
\end{tikzpicture}\hspace{1cm}&\hspace{1cm}
%%%%%%%%%%%%%%%%%%%%
\begin{tikzpicture}[scale=1,thick,>=stealth] 
\vertex (a1) at (0,0) []{};
\vertexs (b1) at (0,-1.5) []{};
\vertex (a2) at (-1.6,-3) []{};
\vertex (a3) at (-.8,-3) []{};
\vertex  [fill=red](a4) at (0,-3) []{};
\vertex  [fill=red](a5) at (.8,-3) []{};
\vertex (a6) at (1.6,-3) []{};
\draw [->] (b1) -- (a1);
\draw [->] (a2) -- (b1);
\draw [->] (a3) -- (b1);
\draw [->] (a4) -- (b1);
\draw [->] (a5) -- (b1);
\draw [->] (a6) -- (b1);
\end{tikzpicture}
\end{array}\]
\caption{}
\end{figure}
\end{document}