Vim-pigraph is a project mainly written in ..., it's free.
Repackaged Pigraph for pathogen
This a version of : http://fmeyer.org/en/pigraph-for-vim-dark-theme.html packaged to work with Tim's Pope pathogen plugin (http://www.vim.org/scripts/script.php?script_id=2332).
To use it (assuming you're using pathogen):
go to your bundle directory (.vim/bundle or .vimbundles) and clone the repo:
git clone [email protected]:jhchabran/vim-pigraph.git
edit your .vimrc and add:
:colorscheme pigraph