1_ The software "gun_antenna.py" uses the module "easygui", which must be loaded. On Linux MX19 (debian), this can be done with :
    "python3 -m pip install easygui"
    
2_ The software "gun_antenna.py" and the file it uses: "lang_US_intro.gif" must be located in the same directory.
From that location, the software is launched with:

    "python3 -m gun_antenna"
    
This is a first version...We have written this program in an elementary way but it is possible to improve it greatly !
