I'm a German engineer and a LaTeX freelancer. I wrote a few packages for LaTeX (some of them are published on CTAN).
If you need explanations to any of my answers, just leave a comment and I'll try to explain, if time permits.
Any (La)TeX code I publish on https://tex.stackexchange.com/ on my behalf I hereby license as Beer-Ware if not explicitly stated otherwise. If you reuse it and publish the resulting code it should contain the following comment:
% ----------------------------------------------------------------------------
% "THE BEER-WARE LICENSE" (Revision 42):
% Jonathan P. Spratte wrote this code. As long as you retain this notice you
% can do whatever you want with this stuff. If we meet some day, and you think
% this stuff is worth it, you can buy me a beer in return. Jonathan P. Spratte
% ----------------------------------------------------------------------------
Any non-TeX code I publish and published on https://tex.stackexchange.com/ on my behalf I hereby license under the terms and conditions of the GPL, version 3 of that license or later, unless explicitly stated otherwise.