% arara: pdflatex
\documentclass{article}
\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
\rule{1cm}{1mm}
\arrow[start anchor={-30}, end anchor={30}]{d}
\arrow[start anchor={-90}, end anchor={90}]{d}
\arrow[start anchor={-150}, end anchor={150}]{d}
\\
\rule{1cm}{1mm} \end{tikzcd}
\end{document}