%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  1. Auflage
%% 
%%  Beispiel 15-02-35 auf Seite 752.
%% 
%%  Copyright (C) 2011 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
verbatimtex
%% 
\documentclass[]{article}
\usepackage[T1]{fontenc}
\begin{document}
etex
% --- start of displayed preamble in the book ---
input boxes;
% --- end of displayed preamble in the book ---
beginfig(1)
circleit.anfang("Box 1");
fill bpath anfang withcolor 0.5[red,white];
circleit.ende(btex \textit{Box 2} etex);
ende.n = anfang.s - (0,1.5cm);
fixsize(anfang,ende);% BB korrigieren
drawboxed(anfang,ende);
drawarrow anfang.s -- ende.n;
drawarrow anfang.w {dir 225} ..
        ende.c cutafter bpath.ende
	withcolor red;
drawdblarrow anfang.e {dir -30} .. ende.e;
endfig;
end;
\end{document}