I dont think this is a perfect solution for the question. Since, the question seems to be interesting, one way to achieve it manually:
\documentclass{article}
\begin{document}
\parindent=0pt
\makeatletter
\def\boxit#1{%
\fboxsep=0pt%
\fboxrule=.1pt%
\@tfor\xx:=#1\do{%
\fbox{\phantom{\xx}}%
} #1%
}
\boxit{Grupa}\\
\boxit{U{\.z}ytkownik{\'o}w}\\
\boxit{Systemu}\\
\boxit{\TeX} %This wont work ;-(
\end{document}
Here, if we pass macros, then it will, for example \boxit{\TeX} will appear in single box rather than in three boxes. Also, for accented characters we need to group it like {\'a} or {\'{a}}. Another problem is that, we need to put the box manually.
fbox? – Sean Allred Jul 06 '13 at 00:34\fboxsepbut I'll need to use\fboxaround every character. – Sigur Jul 06 '13 at 00:38\demoboxcommand. – Gonzalo Medina Jul 06 '13 at 04:03