tcolorbox
可以成为你的新朋友:
\documentclass{article}
\usepackage{xcolor}
\usepackage{tcolorbox}
\begin{document}
\begin{tcolorbox}[
sharp corners,
rounded corners=northeast,
colback=green!35!brown,
colframe=green!35!brown,
arc=5mm,
text width=.85cm
]
\color{white}Test
\end{tcolorbox}
\end{document}