% !TeX TXS-program:compile = txs:///pdflatex

\documentclass[margin=5mm]{standalone}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}[line join=bevel]
	\draw[line width=1.25pt] (0.5,0.5)rectangle (6,6) ; %BCGF
	\draw[line width=1.25pt] (6,0.5)--(8.7,3.2)--(8.7,8.7)--(6,6) ;%CDHG
	\draw[line width=1.25pt] (8.7,8.7)--(3.2,8.7)--(0.5,6) ;%HEF
	\draw[line width=1pt,dashed] (0.5,0.5)--(3.2,3.2)--(8.7,3.2) ;%BAD
	\draw[line width=1pt,dashed] (3.2,3.2)--(3.2,8.7) ;%AE
	\foreach \Coord/\Sommet/\Pos in {(3.2,3.2)/A/below,(0.5,0.5)/B/below,(6,0.5)/C/below,(8.7,3.2)/D/below,(3.2,8.7)/E/above,(0.5,6)/F/above left,(6,6)/G/above,(8.7,8.7)/H/above right,(2.525,8.025)/I/above,(4.575,8.7)/J/above left,(0.5,1.875)/K/left}
	\filldraw \Coord circle[radius=2pt] node[\Pos] {\Sommet} ;
\end{tikzpicture}

\end{document}