https://youtu.be/5A_jgzkpb8g    (3)                           frames, buttons, entry, focus 

https://youtu.be/384OITvbSl0    (8)                           Bind events to actions (globals)

https://www.youtube.com/watch?v=Di5FSglGdNM&t=25s (9)         callback functions, lambda (bind)