The RenderObject Level
Widgets are just blueprints. The real work happens in RenderObject.
The Hierarchy
StatelessWidget -> Element -> RenderObject.
Why Build One?
When you need a custom scrolling effect or a layout that doesn't follow standard rules, RenderObject gives you direct access to the paint and performLayout methods.
Practice: Create a RenderShiftedBox that offsets its child based on the device's gyroscope data.