%% 
%%  Ein Beispiel der DANTE-Edition
%%  Mathematiksatz mit LaTeX
%%  3. Auflage
%%  Beispiel 08-02-8 auf Seite 163.
%%  Copyright (C) 2018 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.
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[10pt]{screxa}
\pagestyle{empty}
\setlength\textwidth{352.81416pt}
\AtBeginDocument{\setlength\parindent{0pt}}
%StartShownPreambleCommands
\def\myRule{%
  \mathchoice{\rule{20pt}{20pt}}{\rule{10pt}{10pt}}{\rule{5pt}{5pt}}{\rule{2.5pt}{2.5pt}}\mkern2mu}
\def\Stil{\mathchoice{D}{T}{S}{SS}\mkern2mu}
%StopShownPreambleCommands
\begin{document}
\large$\myRule\sum\limits_{\myRule i=1}^{\myRule\infty} \qquad
 \myRule\frac{\myRule\sqrt{\myRule i+1}}{\myRule i^{\myRule2}}$
%
$\Stil\sum\limits_{\Stil i=1}^{\Stil\infty} \qquad
 \Stil\frac{\Stil\sqrt{\Stil i+1}}{\Stil i^{\Stil2}}$
\end{document}