How to produce handwritten arrows?

Question

In the article Topologies et Faisceaux by Demazure, one can find the following arrows (well, it is not in the link, but in the book version):

And, out of pure curiosity, I am wondering if it is possible to reproduce this effect in (La)TeX? I think this kind of hand-written arrows are quite fun to read. :)

I don't know if an MWE is needed; I have no clue how to produce this sort of things in TeX at present.

Thanks for any help or reference.

Answer 1

Someone is bound to propose some tikz, but for the authentic hand drawn look, never forget the awesome power of ms paint:

\documentclass{article}

\usepackage{graphics}

\begin{document}

\[
\begin{array}{cccccc}
U_1&\raisebox{-.5\height}{\includegraphics{ra1}}&U_2&
\raisebox{-.5\height}{\includegraphics{ra2}}&U_3\\
\includegraphics{ua1}&&\includegraphics{ua2}&&\includegraphics{ua3}\\
S_1&&S_2&&S_3
\end{array}
\]
\end{document}