\documentclass{article}
\usepackage{web}
\margins{0pt}{0pt}{0pt}{0pt}   %% Kein Seitenrand
\screensize{320mm}{320mm}      %% Dimensionen: H\"{o}he, Breite des Dokuments

\parindent0pt

\usepackage{pstricks,pstricks-add}

\definecolor{switzerlandRed}{HTML}{FF0000} 


\begin{document}

\thispagestyle{empty}

\begin{pspicture}(0,0)(32,32)
%% Flagge (Verh\"{a}ltnis 1 Breite : 1 H\"{o}he)
%% Kreuz: 6 7 6 7 6 : 6 7 6 7 6

\psframe[linecolor=switzerlandRed,fillstyle=solid,fillcolor=switzerlandRed](0,0)(32,32)
\pspolygon[linecolor=white,fillstyle=solid,fillcolor=white](6,13)(13,13)(13,6)(19,6)(19,13)(26,13)(26,19)(19,19)(19,26)(13,26)(13,19)(6,19)


\end{pspicture}
\end{document}
