箭头未显示

Question

我不知道我做错了什么，但从左下角框到右上角框的链接上的箭头没有显示。我希望它与其他边缘上的箭头相同。谢谢。

\documentclass{scrartcl}        

\usepackage{tikz}

\usetikzlibrary{shapes,positioning,arrows}

\tikzstyle{every entity} = []
\tikzstyle{every link} = []
\tikzstyle{smentity} = [rectangle, draw, black, 
                      minimum width=4em, minimum height=2em,
                      every entity]
\tikzstyle{link} = [>=triangle 60, draw, thick, every link]

\begin{document}
\begin{tikzpicture}[node distance=1.5cm, every edge/.style={link}]

\node[smentity] (3)  {0001 1000};
\node[smentity] (4) [right= of 3] {1000 0001} edge[<-,dashed] node[above] {\small{01000}} (3);

\node[smentity] (5) [below= of 3] {1000 0000};
\node[smentity] (6) [right= of 5] {1000 0100} edge[->,dashed] (4);

\draw[>=triangle 60,dashed,thick] (5.east) -- ++(0.8,0) node[below,xshift=-0.4cm]{\small{01000}} -| ++(0,2) -- (4.196);

\end{tikzpicture}
\end{document}