答案1
以薛定谔的猫的评论作为起点:
\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{arrows.meta,
positioning}
\begin{document}
\begin{tikzpicture}[
node distance = 2mm and 8mm,
N/.style = {draw, minimum width=12mm, font=\sffamily},
arr/.style = {draw=blue!60, -{Triangle[fill=blue!60]}},
]
\node (N) [N,rounded corners=2mm, minimum size=24mm] {Network};
\node (a) [N, above left=of N.south west] {A};
\node (d) [N, below left=of N.north west] {D};
\node (b) [N, above right=of N.south east] {B};
\node (c) [N, below right=of N.north east] {C};
\draw[arr] (a) edge (a -| N.west)
(d -| N.west) edge (d)
(b -| N.east) edge (b)
(c) to (c -| N.east);
\coordinate[right=of b] (aux);
\draw[arr] (b) -- (aux) |- (c);
\end{tikzpicture}
\end{document}