Display the Earth Moon System to scale, showing the location of the barycenter.
$ git clone git@github.com:isotopp/earth-moon-system.git
$ cd earth-moon-system
$ python3 -mvenv venv
$ source venv/bin/activate
(venv) $ pip install -r requirements.txt
(venv) $ python earth-moon-system.py
This produces the PNG file in the repo.