\documentclass{article}
\usepackage{snaptodo}
\begin{document}

\section{Before snaptodo}

We the People of the United States, in Order to form a more perfect
Union, establish Justice, insure domestic Tranquility, provide for the
common defence, promote the general Welfare, and secure the Blessings of
Liberty to ourselves and our Posterity, do ordain and establish this
Constitution for the United States of America.

\def\snaptodoexample{%
    \pgfmathtruncatemacro\wc{round(5+rnd*10)}%
    \snaptodo[block rise=5em]{%
        \foreach\w in{1,...,\wc}{%
            \pgfmathsetmacro\l{0.5+rnd*2.5}%
            \rule{\l em}{0.5em}
        }%
    },
}
\catcode`\,=\active
\let,=\snaptodoexample

\section{After snaptodo}

We the People of the United States, in Order to form a more perfect
Union, establish Justice, insure domestic Tranquility, provide for the
common defence, promote the general Welfare, and secure the Blessings of
Liberty to ourselves and our Posterity, do ordain and establish this
Constitution for the United States of America.

\end{document}
