Mwm: an X11 window manager in 20 lines of code

Is KDE too much for you? GNOME tries to do too much? Xfce still a bit too fancy? Do you need something smaller? Even more minimalist? What about a mere 20 lines of code which provide the absolute barest possible minimum of window management functionality?

You need mwm.

This is the smallest, actually usable window manager I know about. Even TinyWM is twice as large. However, it doesn’t let you launch programs, or assign key bindings. mwm does.
↫ Mwm’s GitHub page

It will open a window, and let you switch between windows, that are always fullscreen. No titlebars, no virtual desktops, no menus, no nothing. This is the true minimalist’s experience.