This mechanism has one further added advantage: it can handle interpolation
from intermediate stages to new values. For example, half-way through
a circle-to-square transition, the shape could be changed once more,
causing the animation to need to interpolate to a triangle. So long as
the triangle class can lerpFrom the rounded-square intermediate class,
the transition can be seamlessly performed.

Conclusion

Flutter’s slogan, “everything is a widget,” revolves around building
user interfaces by composing widgets that are, in turn, composed of
progressively more basic widgets. The result of this aggressive
composition is a large number of widgets that require carefully
designed algorithms and data structures to process efficiently.
With some additional design, these data structures also make it
easy for developers to create infinite scrolling lists that build
widgets on demand when they become visible.

Footnotes: