帮助使用 tikz 创建此图像

Question

我不知道如何使用 tikz 和 amsthm 包创建这个定理

Answer 1

\documentclass{article}
\usepackage[most]{tcolorbox}
\usepackage{lipsum}

\newtcbtheorem[auto counter]{mytheorem}{Theorem}{%
    enhanced,
    empty,
    coltitle=black,
    fonttitle=\bfseries,
    lefttitle=1cm,
    attach boxed title to top left={xshift=15mm},
    overlay={\draw (title.west)-|([yshift=15mm]frame.south west);
    \draw ([yshift=-15mm]frame.north east)--([yshift=5mm]frame.south east)--([xshift=-5mm]frame.south east)--++(180:2cm);
    \draw ([yshift=3mm]frame.south east)--([xshift=-3mm]frame.south east);}
}{th}

\begin{document}

\begin{mytheorem}{}{a}
\lipsum[1]
\end{mytheorem}
 
 \begin{mytheorem}{Second theorem}{b}
 As you can see in Theorem~\ref{th:a} \dots
 
\lipsum[1]
\end{mytheorem}
    
\end{document}