Some widgets seem not to appear on screen to the user, but if they are in the widget tree, they will be there somehow, affecting how a child widget looks (such as how it is positioned or styled, for example).
To position a button in the bottom corner of the screen, for example, we could specify a position related to the screen, but as you may have noticed, buttons and other widgets do not have a Position property. So, you might be asking yourself, "How are widgets organized on the screen?" The answer is widgets again. That's right! Flutter provides widgets to compose the layout itself, with positioning, sizing, styling, and so on.
