pst-arrow redefines a lot of the pstricks macros.  

pst-arrow.tex: the TeX file
pst-arrow.sty: the corresponding LaTeX file
pst-arrow-doc.tex: the included doc file

Save the files pst-arrow.sty|tex in a directory, 
which is part of your  local TeX tree. 
Then do not forget to run texhash to update this tree.


%% This program can be redistributed and/or modified under the terms
%% of the LaTeX Project Public License Distributed from CTAN archives
%% in directory macros/latex/base/lppl.txt.

hvoss@tug.org

# $Id: README 136 2021-07-28 09:39:03Z herbert $
