diff --git a/example/pubspec.lock b/example/pubspec.lock
index bf9c481..8a340e1 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -74,13 +74,6 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  js:
-    dependency: transitive
-    description:
-      name: js
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.6.4"
   lints:
     dependency: transitive
     description:
@@ -162,14 +155,14 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.14"
+    version: "0.4.12"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.3"
+    version: "2.1.2"
 sdks:
-  dart: ">=2.18.0 <3.0.0"
+  dart: ">=2.17.1 <3.0.0"
   flutter: ">=1.17.0"
diff --git a/lib/animate.dart b/lib/animate.dart
index d68f6f1..78247db 100644
--- a/lib/animate.dart
+++ b/lib/animate.dart
@@ -170,9 +170,7 @@ class Animate extends StatefulWidget with AnimateManager<Animate> {
     EffectEntry? prior = _lastEntry;
 
     Duration delay = (effect is ThenEffect)
-        ? (effect.delay ?? Duration.zero) +
-            (prior?.delay ?? Duration.zero) +
-            (prior?.duration ?? Duration.zero)
+        ? (effect.delay ?? Duration.zero) + (prior?.delay ?? Duration.zero) + (prior?.duration ?? Duration.zero)
         : effect.delay ?? prior?.delay ?? Duration.zero;
 
     EffectEntry entry = EffectEntry(
@@ -205,8 +203,7 @@ class _AnimateState extends State<Animate> with SingleTickerProviderStateMixin {
 
   @override
   void didUpdateWidget(Animate oldWidget) {
-    if (oldWidget.controller != widget.controller ||
-        oldWidget._duration != widget._duration) {
+    if (oldWidget.controller != widget.controller || oldWidget._duration != widget._duration) {
       _initController();
       _play();
     } else if (oldWidget.adapter != widget.adapter) {
diff --git a/lib/animate_list.dart b/lib/animate_list.dart
index 5d81933..c450dbc 100644
--- a/lib/animate_list.dart
+++ b/lib/animate_list.dart
@@ -29,8 +29,7 @@ import 'flutter_animate.dart';
 ///   )
 /// )
 /// ```
-class AnimateList<T extends Widget> extends ListBase<Widget>
-    with AnimateManager<AnimateList> {
+class AnimateList<T extends Widget> extends ListBase<Widget> with AnimateManager<AnimateList> {
   /// Specifies a default interval to use for new `AnimateList` instances.
   static Duration defaultInterval = Duration.zero;
 
diff --git a/lib/effects/effect.dart b/lib/effect.dart
similarity index 71%
rename from lib/effects/effect.dart
rename to lib/effect.dart
index 79576ba..23e7fce 100644
--- a/lib/effects/effect.dart
+++ b/lib/effect.dart
@@ -1,6 +1,34 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
-import '../flutter_animate.dart';
+import 'flutter_animate.dart';
+
+/// Used to easily create effects that are composed of one or more existing Effects. Provides
+/// syntactic sugar for overrideing build and calling the `composeEffects` method
+/// with a list of effects.
+mixin CompositeEffectMixin on Effect {
+  List<Effect> get effects;
+
+  @override
+  Widget build(BuildContext context, Widget child, AnimationController controller, EffectEntry entry) =>
+      composeEffects(effects, context, child, controller, entry);
+}
+
+/// Adds a begin/end fields and a convenience method for passing them to entry.buildAnimation()
+class BeginEndEffect<T> extends Effect {
+  const BeginEndEffect({super.delay, super.duration, super.curve, this.begin, this.end});
+
+  /// The begin value for the effect. If null, effects should use a reasonable
+  /// default value when appropriate.
+  final T? begin;
+
+  /// The end value for the effect. If null, effects should use a reasonable
+  /// default value when appropriate.
+  final T? end;
+
+  /// Helper method for concrete effects to easily create an Animation<T> from the current begin/end values.
+  Animation<T> buildBeginEndAnimation(AnimationController controller, EffectEntry entry) =>
+      entry.buildTweenedAnimation(controller, Tween(begin: begin, end: end));
+}
 
 /// Class that defines the required interface and helper methods for
 /// all effect classes. Look at the various effects for examples of how
@@ -9,7 +37,9 @@ import '../flutter_animate.dart';
 ///
 /// It can be instantiated and added to Animate, but has no visual effect.
 @immutable
-class Effect<T> {
+class Effect {
+  const Effect({this.delay, this.duration, this.curve});
+
   /// The specified delay for the effect. If null, will use the delay from the
   /// previous effect, or [Duration.zero] if this is the first effect.
   final Duration? delay;
@@ -22,16 +52,6 @@ class Effect<T> {
   /// previous effect, or [Animate.defaultCurve] if this is the first effect.
   final Curve? curve;
 
-  /// The begin value for the effect. If null, effects should use a reasonable
-  /// default value when appropriate.
-  final T? begin;
-
-  /// The end value for the effect. If null, effects should use a reasonable
-  /// default value when appropriate.
-  final T? end;
-
-  const Effect({this.delay, this.duration, this.curve, this.begin, this.end});
-
   /// Builds the widgets necessary to implement the effect, based on the
   /// provided [AnimationController] and [EffectEntry].
   Widget build(
@@ -43,14 +63,19 @@ class Effect<T> {
     return child;
   }
 
-  /// Returns an animation based on the controller, entry, and begin/end values.
-  Animation<T> buildAnimation(
+  /// Calls build on one or more effects, composing them together and returning the resulting widget tree.
+  @protected
+  Widget composeEffects(
+    List<Effect> effects,
+    BuildContext context,
+    Widget child,
     AnimationController controller,
     EffectEntry entry,
   ) {
-    return entry
-        .buildAnimation(controller)
-        .drive(Tween<T>(begin: begin, end: end));
+    for (var f in effects) {
+      child = f.build(context, child, controller, entry);
+    }
+    return child;
   }
 
   /// Returns a ratio corresponding to the beginning of the specified entry.
@@ -68,8 +93,7 @@ class Effect<T> {
   /// Check if the animation is currently running / active.
   bool isAnimationActive(Animation animation) {
     AnimationStatus status = animation.status;
-    return status == AnimationStatus.forward ||
-        status == AnimationStatus.reverse;
+    return status == AnimationStatus.forward || status == AnimationStatus.reverse;
   }
 
   /// Returns an optimized [AnimatedBuilder] that doesn't
@@ -117,7 +141,7 @@ extension EffectExtensions<T> on AnimateManager<T> {
     double? begin,
     double? end,
   }) =>
-      addEffect(Effect(
+      addEffect(BeginEndEffect(
         delay: delay,
         duration: duration,
         curve: curve,
diff --git a/lib/effect_entry.dart b/lib/effect_entry.dart
new file mode 100644
index 0000000..f4f321c
--- /dev/null
+++ b/lib/effect_entry.dart
@@ -0,0 +1,59 @@
+import 'package:flutter/widgets.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+export 'animate.dart';
+export 'animate_list.dart';
+export 'adapters/adapters.dart';
+export 'effects/effects.dart';
+
+export 'extensions/extensions.dart';
+
+/// Because [Effect] classes are immutable and may be reused between multiple
+/// [Animate] (or [AnimateList]) instances, an `EffectEntry` is created to store
+/// values that may be different between instances. For example, due to
+/// `AnimateList interval`, or from inheriting values from prior effects in the chain.
+@immutable
+class EffectEntry {
+  const EffectEntry({
+    required this.effect,
+    required this.delay,
+    required this.duration,
+    required this.curve,
+    required this.owner,
+  });
+
+  /// The delay for this entry.
+  final Duration delay;
+
+  /// The duration for this entry.
+  final Duration duration;
+
+  /// The curve used by this entry.
+  final Curve curve;
+
+  /// The effect associated with this entry.
+  final Effect effect;
+
+  /// The [Animate] instance that created this entry. This can be used by effects
+  /// to read information about the animation. Effects _should not_ modify
+  /// the animation (ex. by calling [Animate.addEffect]).
+  final Animate owner;
+
+  /// The begin time for this entry.
+  Duration get begin => delay;
+
+  /// The end time for this entry.
+  Duration get end => delay + duration;
+
+  /// Builds a sub-animation that runs from 0-1, based on the properties of this entry.
+  Animation<double> buildAnimation(
+    AnimationController controller, {
+    Curve? curve,
+  }) {
+    return buildSubAnimation(controller, begin, end, curve ?? this.curve);
+  }
+
+  /// Builds an sub-animation that runs from the begin and end values of a given [Tween]
+  Animation<T> buildTweenedAnimation<T>(AnimationController controller, Tween<T> tween) =>
+      buildAnimation(controller).drive(tween);
+}
diff --git a/lib/effects/blur_effect.dart b/lib/effects/blur_effect.dart
index 1e8c61d..29d08ba 100644
--- a/lib/effects/blur_effect.dart
+++ b/lib/effects/blur_effect.dart
@@ -6,7 +6,7 @@ import '../flutter_animate.dart';
 /// Effect that animates a blur on the target (via [ImageFiltered])
 /// between the specified begin and end blur radius values. Defaults to a blur radius of `begin=0, end=4`.
 @immutable
-class BlurEffect extends Effect<Offset> {
+class BlurEffect extends BeginEndEffect<Offset> {
   static const Offset neutralValue = Offset(neutralBlur, neutralBlur);
   static const Offset defaultValue = Offset(defaultBlur, defaultBlur);
 
@@ -35,7 +35,7 @@ class BlurEffect extends Effect<Offset> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<Offset> animation = buildAnimation(controller, entry);
+    Animation<Offset> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<Offset>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/callback_effect.dart b/lib/effects/callback_effect.dart
index 472c576..bde4b58 100644
--- a/lib/effects/callback_effect.dart
+++ b/lib/effects/callback_effect.dart
@@ -27,7 +27,7 @@ import '../flutter_animate.dart';
 /// an animation that is driven by an [Adapter] (or manipulated via its controller)
 /// may behave unexpectedly in certain circumstances.
 @immutable
-class CallbackEffect extends Effect<void> {
+class CallbackEffect extends Effect {
   const CallbackEffect({
     Duration? delay,
     Duration? duration,
diff --git a/lib/effects/custom_effect.dart b/lib/effects/custom_effect.dart
index 68d5544..afe4db4 100644
--- a/lib/effects/custom_effect.dart
+++ b/lib/effects/custom_effect.dart
@@ -11,9 +11,9 @@ import '../flutter_animate.dart';
 /// ```
 ///
 /// Note that the above could also be accomplished by creating a custom effect class
-/// that extends [Effect] and utilizes [AnimatedPadding].
+/// that extends [BeginEndEffect] and utilizes [AnimatedPadding].
 @immutable
-class CustomEffect extends Effect<double> {
+class CustomEffect extends BeginEndEffect<double> {
   const CustomEffect({
     required this.builder,
     Duration? delay,
@@ -38,7 +38,7 @@ class CustomEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<double>(
       animation: animation,
       builder: (ctx, __) => builder(ctx, animation.value, child),
diff --git a/lib/effects/effects.dart b/lib/effects/effects.dart
index 591148e..11b9464 100644
--- a/lib/effects/effects.dart
+++ b/lib/effects/effects.dart
@@ -1,6 +1,4 @@
 // collects effect classes for easy import.
-export 'effect.dart';
-
 export 'blur_effect.dart';
 export 'callback_effect.dart';
 export 'custom_effect.dart';
@@ -19,3 +17,7 @@ export 'then_effect.dart';
 export 'tint_effect.dart';
 export 'toggle_effect.dart';
 export 'visibility_effect.dart';
+export 'variations/fade_in.dart';
+export 'variations/fade_out.dart';
+export 'variations/slide_in.dart';
+export 'variations/slide_out.dart';
diff --git a/lib/effects/fade_effect.dart b/lib/effects/fade_effect.dart
index 3363236..e8b8853 100644
--- a/lib/effects/fade_effect.dart
+++ b/lib/effects/fade_effect.dart
@@ -5,7 +5,7 @@ import '../flutter_animate.dart';
 /// Effect that animates the opacity of the target (via [FadeTransition]) between the specified begin and end values.
 /// It defaults to `begin=0, end=1`.
 @immutable
-class FadeEffect extends Effect<double> {
+class FadeEffect extends BeginEndEffect<double> {
   static const double neutralValue = 1.0;
   static const double defaultValue = 0.0;
 
@@ -31,7 +31,7 @@ class FadeEffect extends Effect<double> {
     EffectEntry entry,
   ) {
     return FadeTransition(
-      opacity: buildAnimation(controller, entry),
+      opacity: buildBeginEndAnimation(controller, entry),
       child: child,
     );
   }
@@ -53,36 +53,4 @@ extension FadeEffectExtensions<T> on AnimateManager<T> {
         begin: begin,
         end: end,
       ));
-
-  /// Adds a [fadeIn] extension to [AnimateManager] ([Animate] and [AnimateList]).
-  /// This is identical to the [fade] extension, except it always uses `end=1.0`.
-  T fadeIn({
-    Duration? delay,
-    Duration? duration,
-    Curve? curve,
-    double? begin,
-  }) =>
-      addEffect(FadeEffect(
-        delay: delay,
-        duration: duration,
-        curve: curve,
-        begin: begin ?? FadeEffect.defaultValue,
-        end: 1.0,
-      ));
-
-  /// Adds a [fadeOut] extension to [AnimateManager] ([Animate] and [AnimateList]).
-  /// This is identical to the [fade] extension, except it always uses `end=0.0`.
-  T fadeOut({
-    Duration? delay,
-    Duration? duration,
-    Curve? curve,
-    double? begin,
-  }) =>
-      addEffect(FadeEffect(
-        delay: delay,
-        duration: duration,
-        curve: curve,
-        begin: begin ?? FadeEffect.neutralValue,
-        end: 0.0,
-      ));
 }
diff --git a/lib/effects/flip_effect.dart b/lib/effects/flip_effect.dart
index 78dbe0e..1dd6058 100644
--- a/lib/effects/flip_effect.dart
+++ b/lib/effects/flip_effect.dart
@@ -22,7 +22,7 @@ import '../flutter_animate.dart';
 /// would cause it to rotate around the Y axis — flipping horizontally.
 /// Default is [Axis.vertical].
 @immutable
-class FlipEffect extends Effect<double> {
+class FlipEffect extends BeginEndEffect<double> {
   static const double neutralValue = 0.0;
   static const double defaultValue = -0.5;
 
@@ -60,7 +60,7 @@ class FlipEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<double>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/listen_effect.dart b/lib/effects/listen_effect.dart
index f551796..72a073a 100644
--- a/lib/effects/listen_effect.dart
+++ b/lib/effects/listen_effect.dart
@@ -27,7 +27,7 @@ import '../flutter_animate.dart';
 ///
 /// See also: [CustomEffect] and [CallbackEffect].
 @immutable
-class ListenEffect extends Effect<double> {
+class ListenEffect extends BeginEndEffect<double> {
   const ListenEffect({
     Duration? delay,
     Duration? duration,
diff --git a/lib/effects/move_effect.dart b/lib/effects/move_effect.dart
index fe9bbf2..2c6a3fd 100644
--- a/lib/effects/move_effect.dart
+++ b/lib/effects/move_effect.dart
@@ -8,7 +8,7 @@ import '../flutter_animate.dart';
 ///
 /// To specify offsets relative to the target's size, use [SlideEffect].
 @immutable
-class MoveEffect extends Effect<Offset> {
+class MoveEffect extends BeginEndEffect<Offset> {
   static const Offset neutralValue = Offset(neutralMove, neutralMove);
   static const Offset defaultValue = Offset(neutralMove, defaultMove);
 
@@ -41,7 +41,7 @@ class MoveEffect extends Effect<Offset> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<Offset> animation = buildAnimation(controller, entry);
+    Animation<Offset> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<Offset>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/rotate_effect.dart b/lib/effects/rotate_effect.dart
index 49f371b..b79ec04 100644
--- a/lib/effects/rotate_effect.dart
+++ b/lib/effects/rotate_effect.dart
@@ -10,7 +10,7 @@ import '../flutter_animate.dart';
 /// will occur). For example an alignment of [Alignment.topLeft] would rotate around the top left
 /// corner of the child.
 @immutable
-class RotateEffect extends Effect<double> {
+class RotateEffect extends BeginEndEffect<double> {
   static const double neutralValue = 0.0;
   static const double defaultValue = -1.0;
 
@@ -38,7 +38,7 @@ class RotateEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return RotationTransition(
       turns: animation,
       alignment: alignment ?? Alignment.center,
diff --git a/lib/effects/saturate_effect.dart b/lib/effects/saturate_effect.dart
index 3551070..a7fdc11 100644
--- a/lib/effects/saturate_effect.dart
+++ b/lib/effects/saturate_effect.dart
@@ -13,7 +13,7 @@ import '../flutter_animate.dart';
 ///   .saturate(duration: 2.seconds)
 /// ```
 @immutable
-class SaturateEffect extends Effect<double> {
+class SaturateEffect extends BeginEndEffect<double> {
   static const double neutralValue = 1.0;
   static const double defaultValue = 0.0;
 
@@ -38,7 +38,7 @@ class SaturateEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<double>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/scale_effect.dart b/lib/effects/scale_effect.dart
index c318516..59d9381 100644
--- a/lib/effects/scale_effect.dart
+++ b/lib/effects/scale_effect.dart
@@ -5,7 +5,7 @@ import '../flutter_animate.dart';
 /// Effect that scales the target (via [ScaleTransition]) between the specified begin and end values.
 /// Defaults to `begin=0, end=1`.
 @immutable
-class ScaleEffect extends Effect<Offset> {
+class ScaleEffect extends BeginEndEffect<Offset> {
   static const Offset neutralValue = Offset(neutralScale, neutralScale);
   static const Offset defaultValue = Offset(defaultScale, defaultScale);
 
@@ -36,7 +36,7 @@ class ScaleEffect extends Effect<Offset> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<Offset> animation = buildAnimation(controller, entry);
+    Animation<Offset> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<Offset>(
       animation: animation,
       builder: (_, __) {
@@ -79,8 +79,7 @@ extension ScaleEffectExtensions<T> on AnimateManager<T> {
     double? end,
     Alignment? alignment,
   }) {
-    begin ??=
-        (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
+    begin ??= (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
     end ??= ScaleEffect.neutralScale;
     return addEffect(ScaleEffect(
       delay: delay,
@@ -102,8 +101,7 @@ extension ScaleEffectExtensions<T> on AnimateManager<T> {
     double? end,
     Alignment? alignment,
   }) {
-    begin ??=
-        (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
+    begin ??= (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
     end ??= ScaleEffect.neutralScale;
     return addEffect(ScaleEffect(
       delay: delay,
@@ -125,8 +123,7 @@ extension ScaleEffectExtensions<T> on AnimateManager<T> {
     double? end,
     Alignment? alignment,
   }) {
-    begin ??=
-        (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
+    begin ??= (end == null ? ScaleEffect.defaultScale : ScaleEffect.neutralScale);
     end ??= ScaleEffect.neutralScale;
     return addEffect(ScaleEffect(
       delay: delay,
diff --git a/lib/effects/shake_effect.dart b/lib/effects/shake_effect.dart
index ce8e4ff..e96670d 100644
--- a/lib/effects/shake_effect.dart
+++ b/lib/effects/shake_effect.dart
@@ -22,7 +22,7 @@ import '../flutter_animate.dart';
 /// Text("Hello").animate().shakeX(amount: 10)
 /// ```
 @immutable
-class ShakeEffect extends Effect<double> {
+class ShakeEffect extends BeginEndEffect<double> {
   static const int defaultHz = 8;
   static const double defaultRotation = pi / 36;
   static const double defaultMove = 5;
@@ -60,7 +60,7 @@ class ShakeEffect extends Effect<double> {
     final bool shouldTranslate = offset != Offset.zero;
     if (!shouldRotate && !shouldTranslate) return child;
 
-    final Animation<double> animation = buildAnimation(controller, entry);
+    final Animation<double> animation = buildBeginEndAnimation(controller, entry);
     final int count = (entry.duration.inMilliseconds / 1000 * hz).round();
 
     return getOptimizedBuilder<double>(
diff --git a/lib/effects/shimmer_effect.dart b/lib/effects/shimmer_effect.dart
index 0d25552..26bc043 100644
--- a/lib/effects/shimmer_effect.dart
+++ b/lib/effects/shimmer_effect.dart
@@ -22,7 +22,7 @@ import '../flutter_animate.dart';
 /// * [BlendMode.srcOver] layers the gradient fill over the child (no masking)
 /// * [BlendMode.dstOver] layers the gradient fill under the child (no masking)
 @immutable
-class ShimmerEffect extends Effect<double> {
+class ShimmerEffect extends BeginEndEffect<double> {
   static const Color defaultColor = Color(0x80FFFFFF);
   static const double defaultSize = 1;
   static const double defaultAngle = pi / 12;
@@ -60,7 +60,7 @@ class ShimmerEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<double>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/slide_effect.dart b/lib/effects/slide_effect.dart
index d3c171a..72155b4 100644
--- a/lib/effects/slide_effect.dart
+++ b/lib/effects/slide_effect.dart
@@ -8,7 +8,7 @@ import '../flutter_animate.dart';
 ///
 /// To use pixel offsets instead, use [MoveEffect].
 @immutable
-class SlideEffect extends Effect<Offset> {
+class SlideEffect extends BeginEndEffect<Offset> {
   static const Offset neutralValue = Offset(neutralSlide, neutralSlide);
   static const Offset defaultValue = Offset(neutralSlide, defaultSlide);
 
@@ -37,7 +37,7 @@ class SlideEffect extends Effect<Offset> {
     EffectEntry entry,
   ) {
     return SlideTransition(
-      position: buildAnimation(controller, entry),
+      position: buildBeginEndAnimation(controller, entry),
       child: child,
     );
   }
diff --git a/lib/effects/swap_effect.dart b/lib/effects/swap_effect.dart
index 8a86afc..4736878 100644
--- a/lib/effects/swap_effect.dart
+++ b/lib/effects/swap_effect.dart
@@ -36,7 +36,7 @@ import '../flutter_animate.dart';
 /// [AnimationController]. So, for example, repeating the first animation (the
 /// fade out) via its controller will not affect the second animation (fade in).
 @immutable
-class SwapEffect extends Effect<void> {
+class SwapEffect extends Effect {
   const SwapEffect({
     Duration? delay,
     Duration? duration,
diff --git a/lib/effects/then_effect.dart b/lib/effects/then_effect.dart
index e6ab40f..d9c1433 100644
--- a/lib/effects/then_effect.dart
+++ b/lib/effects/then_effect.dart
@@ -28,16 +28,14 @@ import '../flutter_animate.dart';
 /// subsequent effect. In the example above, it is functionally equivalent to
 /// setting `delay: 1400.ms` on the blur effect.
 @immutable
-class ThenEffect extends Effect<double> {
+class ThenEffect extends Effect {
   // NOTE: this is just an empty effect, the logic happens in Animate
   // when it recognizes the type.
   const ThenEffect({Duration? delay, Duration? duration, Curve? curve})
       : super(delay: delay, duration: duration, curve: curve);
 
   @override
-  Widget build(BuildContext context, Widget child,
-          AnimationController controller, EffectEntry entry) =>
-      child;
+  Widget build(BuildContext context, Widget child, AnimationController controller, EffectEntry entry) => child;
 }
 
 extension ThenEffectExtensions<T> on AnimateManager<T> {
diff --git a/lib/effects/tint_effect.dart b/lib/effects/tint_effect.dart
index 200e592..3d03818 100644
--- a/lib/effects/tint_effect.dart
+++ b/lib/effects/tint_effect.dart
@@ -15,7 +15,7 @@ import '../flutter_animate.dart';
 ///   .tint(color: Colors.blue, end: 0.5, duration: 2.seconds)
 /// ```
 @immutable
-class TintEffect extends Effect<double> {
+class TintEffect extends BeginEndEffect<double> {
   static const double neutralValue = 0.0;
   static const double defaultValue = 1.0;
 
@@ -44,7 +44,7 @@ class TintEffect extends Effect<double> {
     AnimationController controller,
     EffectEntry entry,
   ) {
-    Animation<double> animation = buildAnimation(controller, entry);
+    Animation<double> animation = buildBeginEndAnimation(controller, entry);
     return getOptimizedBuilder<double>(
       animation: animation,
       builder: (_, __) {
diff --git a/lib/effects/toggle_effect.dart b/lib/effects/toggle_effect.dart
index 079ce49..c305537 100644
--- a/lib/effects/toggle_effect.dart
+++ b/lib/effects/toggle_effect.dart
@@ -20,7 +20,7 @@ import '../flutter_animate.dart';
 /// The child of `Animate` is passed through to the builder in the `child` param
 /// (possibly already wrapped by prior effects).
 @immutable
-class ToggleEffect extends Effect<void> {
+class ToggleEffect extends Effect {
   const ToggleEffect({
     Duration? delay,
     Duration? duration,
diff --git a/lib/effects/variations/blur.dart b/lib/effects/variations/blur.dart
new file mode 100644
index 0000000..9df0a50
--- /dev/null
+++ b/lib/effects/variations/blur.dart
@@ -0,0 +1,34 @@
+// ignore_for_file: overridden_fields
+
+import 'package:flutter/widgets.dart';
+
+import '../../flutter_animate.dart';
+
+/* 
+TODO:
+ BlurY
+ BlurXY
+*/
+@immutable
+class BlurXEffect extends BeginEndEffect<double> with CompositeEffectMixin {
+  const BlurXEffect({super.begin, super.end, super.delay, super.duration, super.curve});
+
+  @override
+  List<Effect> get effects => [
+        BlurEffect(
+          begin: Offset(begin ?? BlurEffect.neutralBlur, 0),
+          end: Offset(end ?? (begin == null ? BlurEffect.defaultBlur : BlurEffect.neutralBlur), 0),
+        )
+      ];
+}
+
+extension BlurEffectExtensions<T> on AnimateManager<T> {
+  T blurX({
+    Duration? delay,
+    Duration? duration,
+    Curve? curve,
+    double? begin,
+    double? end,
+  }) =>
+      addEffect(BlurXEffect(delay: delay, duration: duration, curve: curve));
+}
diff --git a/lib/effects/variations/fade_in.dart b/lib/effects/variations/fade_in.dart
new file mode 100644
index 0000000..bcc031e
--- /dev/null
+++ b/lib/effects/variations/fade_in.dart
@@ -0,0 +1,39 @@
+import 'package:flutter/widgets.dart';
+
+import '../../flutter_animate.dart';
+
+/*
+TODO:
+ FadeInDown
+ FadeInLeft
+ FadeInRight
+*/
+
+@immutable
+class FadeInEffect extends Effect with CompositeEffectMixin {
+  const FadeInEffect({super.delay, super.duration, super.curve});
+
+  @override
+  List<Effect> get effects => const [FadeEffect(begin: 0, end: 1)];
+}
+
+@immutable
+class FadeInUpEffect extends Effect with CompositeEffectMixin {
+  const FadeInUpEffect({this.beginY, super.delay, super.duration, super.curve});
+
+  final double? beginY;
+
+  @override
+  List<Effect> get effects => [
+        const FadeInEffect(),
+        SlideInUpEffect(beginY: beginY),
+      ];
+}
+
+extension FadeInEffectExtensions<T> on AnimateManager<T> {
+  T fadeIn({Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(FadeInEffect(delay: delay, duration: duration, curve: curve));
+
+  T fadeInUp({double? beginY, Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(FadeInUpEffect(beginY: beginY, delay: delay, duration: duration, curve: curve));
+}
diff --git a/lib/effects/variations/fade_out.dart b/lib/effects/variations/fade_out.dart
new file mode 100644
index 0000000..2ddd4ba
--- /dev/null
+++ b/lib/effects/variations/fade_out.dart
@@ -0,0 +1,36 @@
+import 'package:flutter/widgets.dart';
+
+import '../../flutter_animate.dart';
+
+/* 
+TODO: 
+FadeOutDown
+FadeOutLeft
+FadeOutRight
+*/
+
+@immutable
+class FadeOutEffect extends Effect with CompositeEffectMixin {
+  const FadeOutEffect({super.delay, super.duration, super.curve});
+
+  @override
+  List<Effect> get effects => const [FadeEffect(begin: 1, end: 0)];
+}
+
+@immutable
+class FadeOutUpEffect extends Effect with CompositeEffectMixin {
+  const FadeOutUpEffect({this.endY, super.delay, super.duration, super.curve});
+
+  final double? endY;
+
+  @override
+  List<Effect> get effects => [const FadeOutEffect(), SlideOutUpEffect(endY: endY)];
+}
+
+extension FadeOutEffectExtensions<T> on AnimateManager<T> {
+  T fadeOut({Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(FadeOutEffect(delay: delay, duration: duration, curve: curve));
+
+  T fadeOutUp({double? endY, Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(FadeOutUpEffect(endY: endY, delay: delay, duration: duration, curve: curve));
+}
diff --git a/lib/effects/variations/slide_in.dart b/lib/effects/variations/slide_in.dart
new file mode 100644
index 0000000..a92ad47
--- /dev/null
+++ b/lib/effects/variations/slide_in.dart
@@ -0,0 +1,27 @@
+import 'package:flutter/widgets.dart';
+
+import '../../flutter_animate.dart';
+
+/* 
+TODO: 
+SlideInDown
+SlideInLeft
+SlideInRight
+*/
+
+@immutable
+class SlideInUpEffect extends Effect with CompositeEffectMixin {
+  const SlideInUpEffect({this.beginY, super.delay, super.duration, super.curve});
+  static const defaultBeginY = -.2;
+  final double? beginY;
+
+  @override
+  List<Effect> get effects => [
+        SlideEffect(begin: Offset(0, beginY ?? defaultBeginY), end: Offset.zero),
+      ];
+}
+
+extension SlideInExtensions<T> on AnimateManager<T> {
+  T slideInUp({double? beginY, Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(SlideInUpEffect(beginY: beginY, delay: delay, duration: duration, curve: curve));
+}
diff --git a/lib/effects/variations/slide_out.dart b/lib/effects/variations/slide_out.dart
new file mode 100644
index 0000000..8ba5a08
--- /dev/null
+++ b/lib/effects/variations/slide_out.dart
@@ -0,0 +1,26 @@
+import 'package:flutter/widgets.dart';
+
+import '../../flutter_animate.dart';
+
+/*
+TODO:
+SlideOutDown
+SlideOutLeft
+SlideOutRight
+*/
+@immutable
+class SlideOutUpEffect extends Effect with CompositeEffectMixin {
+  const SlideOutUpEffect({this.endY, super.delay, super.duration, super.curve});
+  static const defaultEndY = .2;
+  final double? endY;
+
+  @override
+  List<Effect> get effects => [
+        SlideEffect(begin: Offset.zero, end: Offset(0, endY ?? defaultEndY)),
+      ];
+}
+
+extension SlideOutExtensions<T> on AnimateManager<T> {
+  T slideOutUp({double? endY, Duration? delay, Duration? duration, Curve? curve}) =>
+      addEffect(SlideOutUpEffect(endY: endY, delay: delay, duration: duration, curve: curve));
+}
diff --git a/lib/effects/visibility_effect.dart b/lib/effects/visibility_effect.dart
index 4070604..023af1f 100644
--- a/lib/effects/visibility_effect.dart
+++ b/lib/effects/visibility_effect.dart
@@ -8,7 +8,7 @@ import '../flutter_animate.dart';
 /// The `maintain` parameter is assigned to the [Visibility] properties `maintainSize`,
 /// `maintainAnimation`, `maintainState`, `maintainInteractivity` and `maintainSemantics`.
 @immutable
-class VisibilityEffect extends Effect<bool> {
+class VisibilityEffect extends BeginEndEffect<bool> {
   static const bool neutralValue = true;
 
   static const bool defaultMaintain = true;
@@ -29,8 +29,7 @@ class VisibilityEffect extends Effect<bool> {
   final bool maintain;
 
   @override
-  Widget build(BuildContext context, Widget child,
-      AnimationController controller, EffectEntry entry) {
+  Widget build(BuildContext context, Widget child, AnimationController controller, EffectEntry entry) {
     double ratio = getEndRatio(controller, entry);
     return getToggleBuilder(
       animation: controller,
diff --git a/lib/flutter_animate.dart b/lib/flutter_animate.dart
index 97ee505..de6ee44 100644
--- a/lib/flutter_animate.dart
+++ b/lib/flutter_animate.dart
@@ -1,62 +1,16 @@
 import 'package:flutter/widgets.dart';
 
-import 'effects/effects.dart';
-import 'animate.dart';
-import 'animate_list.dart';
+import 'effect.dart';
 
 export 'animate.dart';
 export 'animate_list.dart';
 export 'adapters/adapters.dart';
 export 'effects/effects.dart';
-
+export 'effect_entry.dart';
+export 'effect.dart';
+export 'effects/effects.dart';
 export 'extensions/extensions.dart';
 
-/// Because [Effect] classes are immutable and may be reused between multiple
-/// [Animate] (or [AnimateList]) instances, an `EffectEntry` is created to store
-/// values that may be different between instances. For example, due to
-/// `AnimateList interval`, or from inheriting values from prior effects in the chain.
-@immutable
-class EffectEntry {
-  const EffectEntry({
-    required this.effect,
-    required this.delay,
-    required this.duration,
-    required this.curve,
-    required this.owner,
-  });
-
-  /// The delay for this entry.
-  final Duration delay;
-
-  /// The duration for this entry.
-  final Duration duration;
-
-  /// The curve used by this entry.
-  final Curve curve;
-
-  /// The effect associated with this entry.
-  final Effect effect;
-
-  /// The [Animate] instance that created this entry. This can be used by effects
-  /// to read information about the animation. Effects _should not_ modify
-  /// the animation (ex. by calling [Animate.addEffect]).
-  final Animate owner;
-
-  /// The begin time for this entry.
-  Duration get begin => delay;
-
-  /// The end time for this entry.
-  Duration get end => delay + duration;
-
-  /// Builds a sub-animation based on the properties of this entry.
-  Animation<double> buildAnimation(
-    AnimationController controller, {
-    Curve? curve,
-  }) {
-    return buildSubAnimation(controller, begin, end, curve ?? this.curve);
-  }
-}
-
 /// Builds a sub-animation to the provided controller that runs from start to
 /// end, with the provided curve. For example, it could create an animation that
 /// runs from 300ms to 800ms with an easeOut curve, within a controller that has a
@@ -77,7 +31,7 @@ Animation<double> buildSubAnimation(
   );
 }
 
-/// Provides a common interface for [Animate] and [AnimateList] to attach [Effect] extensions.
+/// Provides a common interface for [Animate] and [AnimateList] to attach [BeginEndEffect] extensions.
 mixin AnimateManager<T> {
   T addEffect(Effect effect) => throw (UnimplementedError());
   T addEffects(List<Effect> effects) {
diff --git a/pubspec.lock b/pubspec.lock
index 7708595..0555ac7 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -60,13 +60,6 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  js:
-    dependency: transitive
-    description:
-      name: js
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.6.4"
   lints:
     dependency: transitive
     description:
@@ -148,14 +141,14 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.14"
+    version: "0.4.12"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.3"
+    version: "2.1.2"
 sdks:
-  dart: ">=2.18.0 <3.0.0"
+  dart: ">=2.17.0 <3.0.0"
   flutter: ">=1.17.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 9e2a7d4..b61f317 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -5,7 +5,7 @@ repository: https://github.com/gskinner/flutter_animate
 issue_tracker: https://github.com/gskinner/flutter_animate/issues
 
 environment:
-  sdk: ">=2.15.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
   flutter: ">=1.17.0"
 
 dependencies:
diff --git a/test/effects/variations/fade_test.dart b/test/effects/variations/fade_test.dart
new file mode 100644
index 0000000..3b7eca0
--- /dev/null
+++ b/test/effects/variations/fade_test.dart
@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../../tester_extensions.dart';
+
+void main() {
+  testWidgets('fade variations', (tester) async {
+    final fadeIn = const FlutterLogo().animate().fadeIn(duration: 1.seconds);
+    await tester.pumpAnimation(fadeIn, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<FadeTransition>((ft) => ft.opacity.value, .75, 'opacity');
+
+    final fadeInUp = const FlutterLogo().animate(key: const ValueKey(1)).fadeInUp(duration: 1.seconds, beginY: -1);
+    await tester.pumpAnimation(fadeInUp, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<FadeTransition>((ft) => ft.opacity.value, .75, 'opacity');
+    tester.expectWidgetWithDouble<SlideTransition>((ft) => ft.position.value.dy, -.25, 'slide');
+
+    final fadeOut = const FlutterLogo().animate(key: const ValueKey(2)).fadeOut(duration: 1.seconds);
+    await tester.pumpAnimation(fadeOut, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<FadeTransition>((ft) => ft.opacity.value, .25, 'opacity');
+
+    final fadeOutUp = const FlutterLogo().animate(key: const ValueKey(3)).fadeOutUp(duration: 1.seconds, endY: 1);
+    await tester.pumpAnimation(fadeOutUp, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<FadeTransition>((ft) => ft.opacity.value, .25, 'opacity');
+    tester.expectWidgetWithDouble<SlideTransition>((ft) => ft.position.value.dy, .75, 'slide');
+  });
+}
diff --git a/test/effects/variations/slide_test.dart b/test/effects/variations/slide_test.dart
new file mode 100644
index 0000000..4747084
--- /dev/null
+++ b/test/effects/variations/slide_test.dart
@@ -0,0 +1,17 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../../tester_extensions.dart';
+
+void main() {
+  testWidgets('slide variations', (tester) async {
+    final slideInUp = const FlutterLogo().animate().slideInUp(duration: 1.seconds, beginY: -1);
+    await tester.pumpAnimation(slideInUp, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<SlideTransition>((ft) => ft.position.value.dy, -.25, 'slide');
+
+    final slideOutUp = const FlutterLogo().animate(key: const ValueKey(1)).slideOutUp(duration: 1.seconds, endY: 1);
+    await tester.pumpAnimation(slideOutUp, initialDelay: 750.ms);
+    tester.expectWidgetWithDouble<SlideTransition>((ft) => ft.position.value.dy, .75, 'slide');
+  });
+}
diff --git a/test/tester_extensions.dart b/test/tester_extensions.dart
index 498e92a..16f6778 100644
--- a/test/tester_extensions.dart
+++ b/test/tester_extensions.dart
@@ -22,7 +22,7 @@ extension TesterExtensions on WidgetTester {
   }) {
     expect(
       widget(findFirst ? find.byType(T).first : find.byType(T).last),
-      isA<T>().having((t) => getValue(t), debugTitle, expectedValue),
+      isA<T>().having((t) => (getValue(t) - expectedValue).abs() < .00000001, debugTitle, true),
     );
   }