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.