#!/bin/bash

TEX=texput.tex
rm -f $TEX

cat >>$TEX <<\EOF
\documentclass[a4paper]{article}
\usepackage[french]{babel}
\usepackage{beautiful}
\usepackage{tikz}
\usetikzlibrary{decorations.text}
\pagestyle{empty}
\begin{document}

\begin{tikzpicture}
\draw[thick,color=black] (0,0) circle (3.2);
\begin{scope}[scale=3]
\clip (0,0) circle (1);
\clip (-0.95,-1) rectangle (0.95,1);
EOF

gp -fq >>$TEX <<\EOF
{
	for(p=3,5,
		for(k=1,2*p,
			r=1/cos(Pi/p/2);
			z=r*exp(I*Pi*(k+1/2)/p);
			a=real(z);
			b=imag(z);
			c=sqrt(r^2-1);
			printf("\\draw (%.5f,%.5f) circle (%.5f);\n",a,b,c);
		);
	);
}
EOF

cat >>$TEX <<\EOF
\end{scope}
\node at (-0.05,0.01) {
\fontsize{41}{0}\selectfont$\boldsymbol{\mathbb{
G\mkern-4mu
A\mkern-5mu
A\mkern-6mu
T\mkern-2mu
I
}}$};
\begin{scope}[yshift=-37mm]
\path[postaction={decorate,decoration={
                reverse path,
                text along path,
                text align/center,
                text={|\large\bfseries|E~A~3~8~9~3}
}}] (10:22mm) arc (10:170:22mm);
\end{scope}
\end{tikzpicture}
\end{document}
EOF

lualatex $TEX

pdfcrop -margins 1 texput{,0}.pdf
fatten texput{0,1}.pdf
fatten texput{1,2}.pdf
fatten texput{2,3}.pdf
pdfcrop texput{3,4}.pdf
mv texput4.pdf stamp.pdf
rm texput*

rm -f texput*