答案1
trapezium
库中的形状对于shapes.geometric
这种情况来说很方便。您还需要添加rounded corners
选项才能获得这些漂亮的圆边。
\documentclass[tikz,border=3pt]{standalone}
\usetikzlibrary{shapes.geometric}
\begin{document}
\begin{tikzpicture}[thick, rounded corners=7pt]
\node(T) [trapezium, inner xsep=1.5pt, minimum height=4em, rotate=-90, draw,label=center:\textsf{next}] {};
\node(S) at(-2,0) {$S$};
\node(S') at(2,0) {$S'$};
\node(R) at(2,-1) {$R$};
\draw [->](S) -- (T);
\draw [->](T) -- (S');
\draw [->](T.90) to[out=0,in=150] (R);
\end{tikzpicture}
\end{document}