en: https://en.wikipedia.org/wiki/Labyrinth_(paper-and-pencil_game)
description: https://en.wikipedia.org/wiki/Ncurses
howto: http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/
git repo: https://github.com/google/googletest
howto: https://blog.jetbrains.com/rscpp/unit-testing-google-test/