\documentclass{article}
\usepackage{l3draw}
\usepackage{graphicx}
\begin{document}
\ExplSyntaxOn
\noindent
\draw_begin:
\draw_path_moveto:n{0cm,0cm}
\draw_path_lineto:n{0cm,4cm}
\draw_path_lineto:n{4cm,0cm}
\draw_path_close:
\draw_path_use_clear:n{clip}
\draw_path_moveto:n{0cm,0cm}
\draw_path_lineto:n{0cm,4cm}
\draw_path_lineto:n{4cm,4cm}
\draw_path_lineto:n{4cm,0cm}
\draw_path_close:
\draw_color_fill:n{red}
\draw_path_use:n{fill}
\draw_end:
\driver_draw_begin:
\driver_draw_moveto:nn{0cm}{0cm}