anchor.diff:  ///
   /// This is the class used to implement the [flipped] getter on curves.
   ///
  -/// ![](https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.png)
  -/// ![](https://flutter.github.io/assets-for-api-docs/assets/animation/curve_flipped_curve.png)
  +/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.mp4}
  +/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_flipped_curve.mp4}
   class FlippedCurve extends Curve {
     /// Creates a flipped curve.
     ///
  
positive.code: 
  /// A curve that is 0.0 until it hits the threshold, then it jumps to 1.0.
  ///
  /// ![](https://flutter.github.io/assets-for-api-docs/assets/animation/curve_threshold.png)
  class Threshold extends Curve {
    /// Creates a threshold curve.
    ///
  
negative.code: /// The curve rises linearly from 0.0 to 1.0 and then falls discontinuously back
  /// to 0.0 each iteration.
  ///
  /// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_sawtooth.mp4}
  class SawTooth extends Curve {
    /// Creates a sawtooth curve.
    ///
  