Flutter's Physics Simulations: The Simulation Class

Flutter's `Simulation` class is the abstract engine for physics-based animations, modeling a 1D object's position (`x`) and velocity (`dx`) over time. Instead of fixed curves, you describe motion with forces like friction, springs, or gravity. It's the foundation for realistic scrolling, bouncy UI, and falling object effects. The footgun: while simulations are queried with a `time` value, they aren't always stateless. A common error is querying with a past time, which can break the simulation's internal logic; always use increasing time values.