%!TEX pdflatex

\documentclass{article}
\usepackage{tikz}
\usepackage{pgf,pgffor}
\usepackage{siunitx}
\sisetup{locale=FR}

\begin{document}

\tikz \draw[thick,rounded corners=8pt] (0,0) -- (0,2) -- (1,3.25) -- (2,2) -- (2,0) -- (0,2) -- (2,2) -- (0,0) -- (2,0);

\end{document}