Classic pencil and paper "dot and boxes" game.
PigPen (dot and boxes) in C++ using SDL2
Install Xcode from the app store, and homebrew, then:
brew install cmake sdl2 sdl2_gfx sdl2_ttf sdl2_image
apt install build-essential cmake clang \
libsdl2-dev libsdl2-gfx-dev \
libsdl2-ttf-dev libsdl2-image-dev
cmake .
make
./pigpen