diff --git a/README.md b/README.md
index 6beeff3..d319517 100644
--- a/README.md
+++ b/README.md
@@ -12,12 +12,12 @@ Also read: [ideas](https://github.com/meduzen/easings/issues/1) for this package
 ## Summary
 
 - [Easings list](#easings-list)
-- [Installation](#installation)
+  - [Reversed easings curves](#reversed-easings-curves)
 - [Usage](#usage)
-- [Options](#options)
+  - [Custom easings](#custom-easings)
+- [Installation](#installation)
   - [Partial import (`$easings`)](#partial-import-easings)
   - [Legacy browsers (`$easings-legacy`)](#legacy-browsers-easings-legacy)
-- [Other easings](#other-easings)
 
 ## Easings list
 
@@ -47,29 +47,12 @@ Aliases for a shorter syntax (not available in Bourbon):
 | Circ | `$in-out-circ`  | `$in-circ`  | `$out-circ` |
 | Back | `$in-out-back`  | `$in-back`  | `$out-back` |
 
-## Installation
-
-1. `npm install easings.scss` pulls the package into your project.
-2. `@import '~easings.scss';` in a SCSS file make all the easings available as SCSS variables in addition to adding them at [`:root`](https://developer.mozilla.org/en-US/docs/Web/CSS/:root) level.
-
-This means the `@import` statement…
-```scss
-@import '~easings.scss';
-```
+### Reversed easings curves
 
-… already outputs:
+For each of these variables, a [reversed curve](https://css-tricks.com/reversing-an-easing-curve) is available by adding the `-r` suffix to the variable name (or its alias). Examples:
 
-```css
-:root {
-  --in-sine: cubic-bezier(0.47, 0, 0.745, 0.715);
-  --out-sine: cubic-bezier(0.39, 0.575, 0.565, 1);
-  --in-out-sine: cubic-bezier(0.445, 0.05, 0.55, 0.95);
-  --in-quad: cubic-bezier(0.55, 0.085, 0.68, 0.53);
-  /* all 18 other easings… */
-  --out-back: cubic-bezier(0.175, 0.885, 0.32, 1.275);
-  --in-out-back: cubic-bezier(0.68, -0.55, 0.265, 1.55);
-}
-```
+- `$ease-in-out-quart-r` is the reversed curve of `$ease-in-out-quart`;
+- `$out-expo-r` is the reversed curve of `$out-expo`.
 
 ## Usage
 
@@ -98,14 +81,76 @@ These syntaxes all lead to the same CSS output:
 
 > 💡 If you use Bourbon, no code change is required. Make sure you `@import` _easings.scss_ **after** _Bourbon_, and you’re all set.
 
-## Options
+### Custom easings
+
+*easings.scss* also adds a `bezier()` function that alias the CSS `cubic-bezier()` one, allowing a shorter syntax for your custom easings.
+
+```scss
+// You can now write this…
+.my-class {
+  transition-timing-function: bezier(.1, .02, 1, .7);
+}
+
+// … instead of
+.my-class {
+  transition-timing-function: cubic-bezier(.1, .02, 1, .7);
+}
+```
+
+If you want to reverse a custom easing curve, you can use the `reverse-bezier()` function (or its alias `r-bezier()`), accepting 1 or 4 parameters.
+
+```scss
+// 4 parameters
+
+.my-class {
+  transition-timing-function: reverse-bezier(.1, .02, 1, .7);
+}
+
+// 1 parameter
+
+$my-easing-not-yet-reversed: .1, .02, 1, .7;
+
+.my-class {
+  transition-timing-function: reverse-bezier($my-easing-not-yet-reversed);
+}
+
+// r-bezier alias
+
+.my-class {
+  transition-timing-function: r-bezier(.1, .02, 1, .7);
+}
+```
+
+## Installation
+
+1. `npm install easings.scss` pulls the package into your project.
+2. `@import '~easings.scss';` in a SCSS file make all the easings available as SCSS variables in addition to adding them at [`:root`](https://developer.mozilla.org/en-US/docs/Web/CSS/:root) level.
+
+This means the `@import` statement…
+```scss
+@import '~easings.scss';
+```
+
+… already outputs:
+
+```css
+:root {
+  --in-sine: cubic-bezier(0.47, 0, 0.745, 0.715);
+  --out-sine: cubic-bezier(0.39, 0.575, 0.565, 1);
+  --in-out-sine: cubic-bezier(0.445, 0.05, 0.55, 0.95);
+  --in-quad: cubic-bezier(0.55, 0.085, 0.68, 0.53);
+  /* all 18 other easings… */
+  --out-back: cubic-bezier(0.175, 0.885, 0.32, 1.275);
+  --in-out-back: cubic-bezier(0.68, -0.55, 0.265, 1.55);
+}
+```
 
 ### Partial import (`$easings`)
 
 If you don’t want to import everything, write an `$easings` list before the `@import` statement:
 
 ```scss
-$easings: 'in-out-quad', 'out-circ', 'in-out-back';
+$easings: 'in-out-quad', 'in-out-quad-r', 'out-circ', 'in-out-back';
 @import '~easings.scss;
 ```
 
@@ -114,16 +159,18 @@ This will only output the needed Custom Properties, instead of the 24 available:
 ```css
 :root {
   --in-out-quad: cubic-bezier(0.455, 0.03, 0.515, 0.955);
+  --in-out-quad-r: cubic-bezier(0.485, 0.045, 0.545, 0.97);
   --out-circ: cubic-bezier(0.075, 0.82, 0.165, 1);
   --in-out-back: cubic-bezier(0.68, -0.55, 0.265, 1.55);
 }
 ```
 
-All the 24 SCSS variables (and their aliases) remain available. In addition, the 24 `cubic-bezier` coordinates are also available with the `-value` suffix:
-
-```scss
-$in-out-cubic-value: 0.645, 0.045, 0.355, 1;
-```
+> 💡Partial import is only impacting the generated custom properties, but all the 48 SCSS variables (and their aliases) remain available. In addition, the 48 `cubic-bezier` coordinates are also available with the `-value` suffix:
+>
+> ```scss
+> $in-out-cubic-value: 0.645, 0.045, 0.355, 1;
+> $in-out-cubic-r-value: 0.645, 0, 0.355, 0.955;
+> ```
 
 ### Legacy browsers (`$easings-legacy`)
 
@@ -156,19 +203,3 @@ Generated CSS:
   transition: opacity 1.3s var(--in-out-circ);
 }
 ```
-
-## Other easings
-
-*easings.scss* also adds a `bezier()` function that alias the CSS `cubic-bezier()` one, allowing a shorter syntax for your custom easings.
-
-```scss
-// You can now write this…
-.my-class {
-  transition-timing-function: bezier(.1, .02, 1, .7);
-}
-
-// … instead of
-.my-class {
-  transition-timing-function: cubic-bezier(.1, .02, 1, .7);
-}
-```
diff --git a/package.json b/package.json
index 742b1f4..a93476c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "easings.scss",
-  "version": "0.2.1",
+  "version": "0.3.0",
   "description": "Easings (cubic-bezier timing functions) as custom properties and SCSS variables.",
   "main": "src/easings.scss",
   "scripts": {
diff --git a/src/easings.scss b/src/easings.scss
index 98cd60d..cdbe867 100644
--- a/src/easings.scss
+++ b/src/easings.scss
@@ -1,4 +1,4 @@
-@import 'functions/bezier';
+@import 'functions/functions';
 @import 'easings/easings';
 
 /**
diff --git a/src/easings/_in-back.scss b/src/easings/_in-back.scss
deleted file mode 100644
index e5c4352..0000000
--- a/src/easings/_in-back.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-back-value: .6, -.28, .735, .045;
-$in-back: get-bezier('in-back', $in-back-value);
-$ease-in-back: get-bezier('in-back', $in-back-value);
diff --git a/src/easings/_in-circ.scss b/src/easings/_in-circ.scss
deleted file mode 100644
index af89dd8..0000000
--- a/src/easings/_in-circ.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-circ-value: .6, .04, .98, .335;
-$in-circ: get-bezier('in-circ', $in-circ-value);
-$ease-in-circ: get-bezier('in-circ', $in-circ-value);
diff --git a/src/easings/_in-cubic.scss b/src/easings/_in-cubic.scss
deleted file mode 100644
index 38edf40..0000000
--- a/src/easings/_in-cubic.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-cubic-value: .55, .055, .675, .19;
-$in-cubic: get-bezier('in-cubic', $in-cubic-value);
-$ease-in-cubic: get-bezier('in-cubic', $in-cubic-value);
diff --git a/src/easings/_in-expo.scss b/src/easings/_in-expo.scss
deleted file mode 100644
index b40d4f2..0000000
--- a/src/easings/_in-expo.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-expo-value: .95, .05, .795, .035;
-$in-expo: get-bezier('in-expo', $in-expo-value);
-$ease-in-expo: get-bezier('in-expo', $in-expo-value);
diff --git a/src/easings/_in-out-back.scss b/src/easings/_in-out-back.scss
deleted file mode 100644
index 766a324..0000000
--- a/src/easings/_in-out-back.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-back-value: .68, -.55, .265, 1.55;
-$in-out-back: get-bezier('in-out-back', $in-out-back-value);
-$ease-in-out-back: get-bezier('in-out-back', $in-out-back-value);
diff --git a/src/easings/_in-out-circ.scss b/src/easings/_in-out-circ.scss
deleted file mode 100644
index 3debcbd..0000000
--- a/src/easings/_in-out-circ.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-circ-value: .785, .135, .15, .86;
-$in-out-circ: get-bezier('in-out-circ', $in-out-circ-value);
-$ease-in-out-circ: get-bezier('in-out-circ', $in-out-circ-value);
diff --git a/src/easings/_in-out-cubic.scss b/src/easings/_in-out-cubic.scss
deleted file mode 100644
index b13d203..0000000
--- a/src/easings/_in-out-cubic.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-cubic-value: .645, .045, .355, 1;
-$in-out-cubic: get-bezier('in-out-cubic', $in-out-cubic-value);
-$ease-in-out-cubic: get-bezier('in-out-cubic', $in-out-cubic-value);
diff --git a/src/easings/_in-out-expo.scss b/src/easings/_in-out-expo.scss
deleted file mode 100644
index 80e3fee..0000000
--- a/src/easings/_in-out-expo.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-expo-value: 1, 0, 0, 1;
-$in-out-expo: get-bezier('in-out-expo', $in-out-expo-value);
-$ease-in-out-expo: get-bezier('in-out-expo', $in-out-expo-value);
diff --git a/src/easings/_in-out-quad.scss b/src/easings/_in-out-quad.scss
deleted file mode 100644
index 36db9a1..0000000
--- a/src/easings/_in-out-quad.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-quad-value: .455, .03, .515, .955;
-$in-out-quad: get-bezier('in-out-quad', $in-out-quad-value);
-$ease-in-out-quad: get-bezier('in-out-quad', $in-out-quad-value);
diff --git a/src/easings/_in-out-quart.scss b/src/easings/_in-out-quart.scss
deleted file mode 100644
index e85c6a2..0000000
--- a/src/easings/_in-out-quart.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-quart-value: .77, 0, .175, 1;
-$in-out-quart: get-bezier('in-out-quart', $in-out-quart-value);
-$ease-in-out-quart: get-bezier('in-out-quart', $in-out-quart-value);
diff --git a/src/easings/_in-out-quint.scss b/src/easings/_in-out-quint.scss
deleted file mode 100644
index da6f359..0000000
--- a/src/easings/_in-out-quint.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-quint-value: .86, 0, .07, 1;
-$in-out-quint: get-bezier('in-out-quint', $in-out-quint-value);
-$ease-in-out-quint: get-bezier('in-out-quint', $in-out-quint-value);
diff --git a/src/easings/_in-out-sine.scss b/src/easings/_in-out-sine.scss
deleted file mode 100644
index 97ab151..0000000
--- a/src/easings/_in-out-sine.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-out-sine-value: .445, .05, .55, .95;
-$in-out-sine: get-bezier('in-out-sine', $in-out-sine-value);
-$ease-in-out-sine: get-bezier('in-out-sine', $in-out-sine-value);
diff --git a/src/easings/_in-quad.scss b/src/easings/_in-quad.scss
deleted file mode 100644
index 7bb89f8..0000000
--- a/src/easings/_in-quad.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-quad-value: .55, .085, .68, .53;
-$in-quad: get-bezier('in-quad', $in-quad-value);
-$ease-in-quad: get-bezier('in-quad', $in-quad-value);
diff --git a/src/easings/_in-quart.scss b/src/easings/_in-quart.scss
deleted file mode 100644
index 2ba6399..0000000
--- a/src/easings/_in-quart.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-quart-value: .895, .03, .685, .22;
-$in-quart: get-bezier('in-quart', $in-quart-value);
-$ease-in-quart: get-bezier('in-quart', $in-quart-value);
diff --git a/src/easings/_in-quint.scss b/src/easings/_in-quint.scss
deleted file mode 100644
index 3b70dc6..0000000
--- a/src/easings/_in-quint.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-quint-value: .755, .05, .855, .06;
-$in-quint: get-bezier('in-quint', $in-quint-value);
-$ease-in-quint: get-bezier('in-quint', $in-quint-value);
diff --git a/src/easings/_in-sine.scss b/src/easings/_in-sine.scss
deleted file mode 100644
index 1df4a32..0000000
--- a/src/easings/_in-sine.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$in-sine-value: .47, 0, .745, .715;
-$in-sine: get-bezier('in-sine', $in-sine-value);
-$ease-in-sine: get-bezier('in-sine', $in-sine-value);
diff --git a/src/easings/_list-and-mapping.scss b/src/easings/_list-and-mapping.scss
new file mode 100644
index 0000000..034624d
--- /dev/null
+++ b/src/easings/_list-and-mapping.scss
@@ -0,0 +1,121 @@
+/**
+ * The value associated to each easing
+ */
+$easings-map: (
+  'in-sine': $in-sine-value,
+  'in-sine-r': $in-sine-r-value,
+  'out-sine': $out-sine-value,
+  'out-sine-r': $out-sine-r-value,
+  'in-out-sine': $in-out-sine-value,
+  'in-out-sine-r': $in-out-sine-r-value,
+
+  'in-quad': $in-quad-value,
+  'in-quad-r': $in-quad-r-value,
+  'out-quad': $out-quad-value,
+  'out-quad-r': $out-quad-r-value,
+  'in-out-quad': $in-out-quad-value,
+  'in-out-quad-r': $in-out-quad-r-value,
+
+  'in-cubic': $in-cubic-value,
+  'in-cubic-r': $in-cubic-r-value,
+  'out-cubic': $out-cubic-value,
+  'out-cubic-r': $out-cubic-r-value,
+  'in-out-cubic': $in-out-cubic-value,
+  'in-out-cubic-r': $in-out-cubic-r-value,
+
+  'in-quart': $in-quart-value,
+  'in-quart-r': $in-quart-r-value,
+  'out-quart': $out-quart-value,
+  'out-quart-r': $out-quart-r-value,
+  'in-out-quart': $in-out-quart-value,
+  'in-out-quart-r': $in-out-quart-r-value,
+
+  'in-quint': $in-quint-value,
+  'in-quint-r': $in-quint-r-value,
+  'out-quint': $out-quint-value,
+  'out-quint-r': $out-quint-r-value,
+  'in-out-quint': $in-out-quint-value,
+  'in-out-quint-r': $in-out-quint-r-value,
+
+  'in-expo': $in-expo-value,
+  'in-expo-r': $in-expo-r-value,
+  'out-expo': $out-expo-value,
+  'out-expo-r': $out-expo-r-value,
+  'in-out-expo': $in-out-expo-value,
+  'in-out-expo-r': $in-out-expo-r-value,
+
+  'in-circ': $in-circ-value,
+  'in-circ-r': $in-circ-r-value,
+  'out-circ': $out-circ-value,
+  'out-circ-r': $out-circ-r-value,
+  'in-out-circ': $in-out-circ-value,
+  'in-out-circ-r': $in-out-circ-r-value,
+
+  'in-back': $in-back-value,
+  'in-back-r': $in-back-r-value,
+  'out-back': $out-back-value,
+  'out-back-r': $out-back-r-value,
+  'in-out-back': $in-out-back-value,
+  'in-out-back-r': $in-out-back-r-value,
+);
+
+/**
+ * Available easings
+ */
+$easings-list: (
+  'in-sine',
+  'in-sine-r',
+  'out-sine',
+  'out-sine-r',
+  'in-out-sine',
+  'in-out-sine-r',
+
+  'in-quad',
+  'in-quad-r',
+  'out-quad',
+  'out-quad-r',
+  'in-out-quad',
+  'in-out-quad-r',
+
+  'in-cubic',
+  'in-cubic-r',
+  'out-cubic',
+  'out-cubic-r',
+  'in-out-cubic',
+  'in-out-cubic-r',
+
+  'in-quart',
+  'in-quart-r',
+  'out-quart',
+  'out-quart-r',
+  'in-out-quart',
+  'in-out-quart-r',
+
+  'in-quint',
+  'in-quint-r',
+  'out-quint',
+  'out-quint-r',
+  'in-out-quint',
+  'in-out-quint-r',
+
+  'in-expo',
+  'in-expo-r',
+  'out-expo',
+  'out-expo-r',
+  'in-out-expo',
+  'in-out-expo-r',
+
+  'in-circ',
+  'in-circ-r',
+  'out-circ',
+  'out-circ-r',
+  'in-out-circ',
+  'in-out-circ-r',
+
+  'in-back',
+  'in-back-r',
+  'out-back',
+  'out-back-r',
+  'in-out-back',
+  'in-out-back-r',
+);
diff --git a/src/easings/_out-back.scss b/src/easings/_out-back.scss
deleted file mode 100644
index d878ba0..0000000
--- a/src/easings/_out-back.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-back-value: .175, .885, .32, 1.275;
-$out-back: get-bezier('out-back', $out-back-value);
-$ease-out-back: get-bezier('out-back', $out-back-value);
diff --git a/src/easings/_out-circ.scss b/src/easings/_out-circ.scss
deleted file mode 100644
index 9550b09..0000000
--- a/src/easings/_out-circ.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-circ-value: .075, .82, .165, 1;
-$out-circ: get-bezier('out-circ', $out-circ-value);
-$ease-out-circ: get-bezier('out-circ', $out-circ-value);
diff --git a/src/easings/_out-cubic.scss b/src/easings/_out-cubic.scss
deleted file mode 100644
index 9826ddc..0000000
--- a/src/easings/_out-cubic.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-cubic-value: .215, .61, .355, 1;
-$out-cubic: get-bezier('out-cubic', $out-cubic-value);
-$ease-out-cubic: get-bezier('out-cubic', $out-cubic-value);
diff --git a/src/easings/_out-expo.scss b/src/easings/_out-expo.scss
deleted file mode 100644
index 502600b..0000000
--- a/src/easings/_out-expo.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-expo-value: .19, 1, .22, 1;
-$out-expo: get-bezier('out-expo', $out-expo-value);
-$ease-out-expo: get-bezier('out-expo', $out-expo-value);
diff --git a/src/easings/_out-quad.scss b/src/easings/_out-quad.scss
deleted file mode 100644
index 555917f..0000000
--- a/src/easings/_out-quad.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-quad-value: .25, .46, .45, .94;
-$out-quad: get-bezier('out-quad', $out-quad-value);
-$ease-out-quad: get-bezier('out-quad', $out-quad-value);
diff --git a/src/easings/_out-quart.scss b/src/easings/_out-quart.scss
deleted file mode 100644
index 20a1490..0000000
--- a/src/easings/_out-quart.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-quart-value: .165, .84, .44, 1;
-$out-quart: get-bezier('out-quart', $out-quart-value);
-$ease-out-quart: get-bezier('out-quart', $out-quart-value);
diff --git a/src/easings/_out-quint.scss b/src/easings/_out-quint.scss
deleted file mode 100644
index 302206f..0000000
--- a/src/easings/_out-quint.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-quint-value: .23, 1, .32, 1;
-$out-quint: get-bezier('out-quint', $out-quint-value);
-$ease-out-quint: get-bezier('out-quint', $out-quint-value);
diff --git a/src/easings/_out-sine.scss b/src/easings/_out-sine.scss
deleted file mode 100644
index 2fc226f..0000000
--- a/src/easings/_out-sine.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$out-sine-value: .39, .575, .565, 1;
-$out-sine: get-bezier('out-sine', $out-sine-value);
-$ease-out-sine: get-bezier('out-sine', $out-sine-value);
diff --git a/src/easings/_timings.scss b/src/easings/_timings.scss
new file mode 100644
index 0000000..10ead73
--- /dev/null
+++ b/src/easings/_timings.scss
@@ -0,0 +1,36 @@
+/**
+ * The four esaings coordinates for each easing
+ */
+$easings-values: (
+  'in-sine': ('x1': .47, 'y1': 0, 'x2': .745, 'y2': .715),
+  'out-sine': ('x1': .39, 'y1': .575, 'x2': .565, 'y2': 1),
+  'in-out-sine': ('x1': .445, 'y1': .05, 'x2': .55, 'y2': .95),
+
+  'in-quad': ('x1': .55, 'y1': .085, 'x2': .68, 'y2': .53),
+  'out-quad': ('x1': .25, 'y1': .46, 'x2': .45, 'y2': .94),
+  'in-out-quad': ('x1': .455, 'y1': .03, 'x2': .515, 'y2': .955),
+
+  'in-cubic': ('x1': .55, 'y1': .055, 'x2': .675, 'y2': .19),
+  'out-cubic': ('x1': .215, 'y1': .61, 'x2': .355, 'y2': 1),
+  'in-out-cubic': ('x1': .645, 'y1': .045, 'x2': .355, 'y2': 1),
+
+  'in-quart': ('x1': .895, 'y1': .03, 'x2': .685, 'y2': .22),
+  'out-quart': ('x1': .165, 'y1': .84, 'x2': .44, 'y2': 1),
+  'in-out-quart': ('x1': .77, 'y1': 0, 'x2': .175, 'y2': 1),
+
+  'in-quint': ('x1': .755, 'y1': .05, 'x2': .855, 'y2': .06),
+  'out-quint': ('x1': .23, 'y1': 1, 'x2': .32, 'y2': 1),
+  'in-out-quint': ('x1': .86, 'y1': 0, 'x2': .07, 'y2': 1),
+
+  'in-expo': ('x1': .95, 'y1': .05, 'x2': .795, 'y2': .035),
+  'out-expo': ('x1': .19, 'y1': 1, 'x2': .22, 'y2': 1),
+  'in-out-expo': ('x1': 1, 'y1': 0, 'x2': 0, 'y2': 1),
+
+  'in-circ': ('x1': .6, 'y1': .04, 'x2': .98, 'y2': .335),
+  'out-circ': ('x1': .075, 'y1': .82, 'x2': .165, 'y2': 1),
+  'in-out-circ': ('x1': .785, 'y1': .135, 'x2': .15, 'y2': .86),
+
+  'in-back': ('x1': .6, 'y1': -.28, 'x2': .735, 'y2': .045),
+  'out-back': ('x1': .175, 'y1': .885, 'x2': .32, 'y2': 1.275),
+  'in-out-back': ('x1': .68, 'y1': -.55, 'x2': .265, 'y2': 1.55),
+);
diff --git a/src/easings/_variables.scss b/src/easings/_variables.scss
new file mode 100644
index 0000000..b602f53
--- /dev/null
+++ b/src/easings/_variables.scss
@@ -0,0 +1,252 @@
+/**
+ * Available variables
+ *
+ * How it works:
+ *
+ * $in-[easingName]-value: coordinates (e.g, `.47, 0, .745, .715`).
+ * $in-[easingName]-r-value: coordinates for reversed easing.
+ *
+ * $in-[easingName]: see functions/helpers.
+ * $ease-in-[easingName]: alias for previous line.
+ * $in-[easingName]-r: reverse for previous line.
+ * $ease-in-[easingName]-r: alias for previous line.
+ */
+
+// in-sine
+
+$in-sine-value: bezier-x1(in-sine), bezier-y1(in-sine), bezier-x2(in-sine), bezier-y2(in-sine);
+$in-sine-r-value: reverse-bezier-value(in-sine);
+
+$in-sine: get-bezier('in-sine', $in-sine-value);
+$ease-in-sine: $in-sine;
+$in-sine-r: get-bezier('in-sine-r', $in-sine-r-value);
+$ease-in-sine-r: $in-sine-r;
+
+// out-sine
+
+$out-sine-value: bezier-x1(out-sine), bezier-y1(out-sine), bezier-x2(out-sine), bezier-y2(out-sine);
+$out-sine-r-value: reverse-bezier-value(out-sine);
+
+$out-sine: get-bezier('out-sine', $out-sine-value);
+$ease-out-sine: $out-sine;
+$out-sine-r: get-bezier('out-sine-r', $out-sine-r-value);
+$ease-out-sine-r: $out-sine-r;
+
+// in-out-sine
+
+$in-out-sine-value: bezier-x1(in-out-sine), bezier-y1(in-out-sine), bezier-x2(in-out-sine), bezier-y2(in-out-sine);
+$in-out-sine-r-value: reverse-bezier-value(in-out-sine);
+
+$in-out-sine: get-bezier('in-out-sine', $in-out-sine-value);
+$ease-in-out-sine: $in-out-sine;
+$in-out-sine-r: get-bezier('in-out-sine-r', $in-out-sine-r-value);
+$ease-in-out-sine-r: $in-out-sine-r;
+
+// in-quad
+
+$in-quad-value: bezier-x1(in-quad), bezier-y1(in-quad), bezier-x2(in-quad), bezier-y2(in-quad);
+$in-quad-r-value: reverse-bezier-value(in-quad);
+
+$in-quad: get-bezier('in-quad', $in-quad-value);
+$ease-in-quad: $in-quad;
+$in-quad-r: get-bezier('in-quad-r', $in-quad-r-value);
+$ease-in-quad-r: $in-quad-r;
+
+// out-quad
+
+$out-quad-value: bezier-x1(out-quad), bezier-y1(out-quad), bezier-x2(out-quad), bezier-y2(out-quad);
+$out-quad-r-value: reverse-bezier-value(out-quad);
+
+$out-quad: get-bezier('out-quad', $out-quad-value);
+$ease-out-quad: $out-quad;
+$out-quad-r: get-bezier('out-quad-r', $out-quad-r-value);
+$ease-out-quad-r: $out-quad-r;
+
+// in-out-quad
+
+$in-out-quad-value: bezier-x1(in-out-quad), bezier-y1(in-out-quad), bezier-x2(in-out-quad), bezier-y2(in-out-quad);
+$in-out-quad-r-value: reverse-bezier-value(in-out-quad);
+
+$in-out-quad: get-bezier('in-out-quad', $in-out-quad-value);
+$ease-in-out-quad: $in-out-quad;
+$in-out-quad-r: get-bezier('in-out-quad-r', $in-out-quad-r-value);
+$ease-in-out-quad-r: $in-out-quad-r;
+
+// in-cubic
+
+$in-cubic-value: bezier-x1(in-cubic), bezier-y1(in-cubic), bezier-x2(in-cubic), bezier-y2(in-cubic);
+$in-cubic-r-value: reverse-bezier-value(in-cubic);
+
+$in-cubic: get-bezier('in-cubic', $in-cubic-value);
+$ease-in-cubic: $in-cubic;
+$in-cubic-r: get-bezier('in-cubic-r', $in-cubic-r-value);
+$ease-in-cubic-r: $in-cubic-r;
+
+// out-cubic
+
+$out-cubic-value: bezier-x1(out-cubic), bezier-y1(out-cubic), bezier-x2(out-cubic), bezier-y2(out-cubic);
+$out-cubic-r-value: reverse-bezier-value(out-cubic);
+
+$out-cubic: get-bezier('out-cubic', $out-cubic-value);
+$ease-out-cubic: $out-cubic;
+$out-cubic-r: get-bezier('out-cubic-r', $out-cubic-r-value);
+$ease-out-cubic-r: $out-cubic-r;
+
+// in-out-cubic
+
+$in-out-cubic-value: bezier-x1(in-out-cubic), bezier-y1(in-out-cubic), bezier-x2(in-out-cubic), bezier-y2(in-out-cubic);
+$in-out-cubic-r-value: reverse-bezier-value(in-out-cubic);
+
+$in-out-cubic: get-bezier('in-out-cubic', $in-out-cubic-value);
+$ease-in-out-cubic: $in-out-cubic;
+$in-out-cubic-r: get-bezier('in-out-cubic-r', $in-out-cubic-r-value);
+$ease-in-out-cubic-r: $in-out-cubic-r;
+
+// in-quart
+
+$in-quart-value: bezier-x1(in-quart), bezier-y1(in-quart), bezier-x2(in-quart), bezier-y2(in-quart);
+$in-quart-r-value: reverse-bezier-value(in-quart);
+
+$in-quart: get-bezier('in-quart', $in-quart-value);
+$ease-in-quart: $in-quart;
+$in-quart-r: get-bezier('in-quart-r', $in-quart-r-value);
+$ease-in-quart-r: $in-quart-r;
+
+// out-quart
+
+$out-quart-value: bezier-x1(out-quart), bezier-y1(out-quart), bezier-x2(out-quart), bezier-y2(out-quart);
+$out-quart-r-value: reverse-bezier-value(out-quart);
+
+$out-quart: get-bezier('out-quart', $out-quart-value);
+$ease-out-quart: $out-quart;
+$out-quart-r: get-bezier('out-quart-r', $out-quart-r-value);
+$ease-out-quart-r: $out-quart-r;
+
+// in-out-quart
+
+$in-out-quart-value: bezier-x1(in-out-quart), bezier-y1(in-out-quart), bezier-x2(in-out-quart), bezier-y2(in-out-quart);
+$in-out-quart-r-value: reverse-bezier-value(in-out-quart);
+
+$in-out-quart: get-bezier('in-out-quart', $in-out-quart-value);
+$ease-in-out-quart: $in-out-quart;
+$in-out-quart-r: get-bezier('in-out-quart-r', $in-out-quart-r-value);
+$ease-in-out-quart-r: $in-out-quart-r;
+
+// in-quint
+
+$in-quint-value: bezier-x1(in-quint), bezier-y1(in-quint), bezier-x2(in-quint), bezier-y2(in-quint);
+$in-quint-r-value: reverse-bezier-value(in-quint);
+
+$in-quint: get-bezier('in-quint', $in-quint-value);
+$ease-in-quint: $in-quint;
+$in-quint-r: get-bezier('in-quint-r', $in-quint-r-value);
+$ease-in-quint-r: $in-quint-r;
+
+// out-quint
+
+$out-quint-value: bezier-x1(out-quint), bezier-y1(out-quint), bezier-x2(out-quint), bezier-y2(out-quint);
+$out-quint-r-value: reverse-bezier-value(out-quint);
+
+$out-quint: get-bezier('out-quint', $out-quint-value);
+$ease-out-quint: $out-quint;
+$out-quint-r: get-bezier('out-quint-r', $out-quint-r-value);
+$ease-out-quint-r: $out-quint-r;
+
+// in-out-quint
+
+$in-out-quint-value: bezier-x1(in-out-quint), bezier-y1(in-out-quint), bezier-x2(in-out-quint), bezier-y2(in-out-quint);
+$in-out-quint-r-value: reverse-bezier-value(in-out-quint);
+
+$in-out-quint: get-bezier('in-out-quint', $in-out-quint-value);
+$ease-in-out-quint: $in-out-quint;
+$in-out-quint-r: get-bezier('in-out-quint-r', $in-out-quint-r-value);
+$ease-in-out-quint-r: $in-out-quint-r;
+
+// in-expo
+
+$in-expo-value: bezier-x1(in-expo), bezier-y1(in-expo), bezier-x2(in-expo), bezier-y2(in-expo);
+$in-expo-r-value: reverse-bezier-value(in-expo);
+
+$in-expo: get-bezier('in-expo', $in-expo-value);
+$ease-in-expo: $in-expo;
+$in-expo-r: get-bezier('in-expo-r', $in-expo-r-value);
+$ease-in-expo-r: $in-expo-r;
+
+// out-expo
+
+$out-expo-value: bezier-x1(out-expo), bezier-y1(out-expo), bezier-x2(out-expo), bezier-y2(out-expo);
+$out-expo-r-value: reverse-bezier-value(out-expo);
+
+$out-expo: get-bezier('out-expo', $out-expo-value);
+$ease-out-expo: $out-expo;
+$out-expo-r: get-bezier('out-expo-r', $out-expo-r-value);
+$ease-out-expo-r: $out-expo-r;
+
+// in-out-expo
+
+$in-out-expo-value: bezier-x1(in-out-expo), bezier-y1(in-out-expo), bezier-x2(in-out-expo), bezier-y2(in-out-expo);
+$in-out-expo-r-value: reverse-bezier-value(in-out-expo);
+
+$in-out-expo: get-bezier('in-out-expo', $in-out-expo-value);
+$ease-in-out-expo: $in-out-expo;
+$in-out-expo-r: get-bezier('in-out-expo-r', $in-out-expo-r-value);
+$ease-in-out-expo-r: $in-out-expo-r;
+
+// in-circ
+
+$in-circ-value: bezier-x1(in-circ), bezier-y1(in-circ), bezier-x2(in-circ), bezier-y2(in-circ);
+$in-circ-r-value: reverse-bezier-value(in-circ);
+$in-circ: get-bezier('in-circ', $in-circ-value);
+$ease-in-circ: $in-circ;
+$in-circ-r: get-bezier('in-circ-r', $in-circ-r-value);
+$ease-in-circ-r: $in-circ-r;
+
+// out-circ
+
+$out-circ-value: bezier-x1(out-circ), bezier-y1(out-circ), bezier-x2(out-circ), bezier-y2(out-circ);
+$out-circ-r-value: reverse-bezier-value(out-circ);
+
+$out-circ: get-bezier('out-circ', $out-circ-value);
+$ease-out-circ: $out-circ;
+$out-circ-r: get-bezier('out-circ-r', $out-circ-r-value);
+$ease-out-circ-r: $out-circ-r;
+
+// in-out-circ
+
+$in-out-circ-value: bezier-x1(in-out-circ), bezier-y1(in-out-circ), bezier-x2(in-out-circ), bezier-y2(in-out-circ);
+$in-out-circ-r-value: reverse-bezier-value(in-out-circ);
+
+$in-out-circ: get-bezier('in-out-circ', $in-out-circ-value);
+$ease-in-out-circ: $in-out-circ;
+$in-out-circ-r: get-bezier('in-out-circ-r', $in-out-circ-r-value);
+$ease-in-out-circ-r: $in-out-circ-r;
+
+// in-back
+
+$in-back-value: bezier-x1(in-back), bezier-y1(in-back), bezier-x2(in-back), bezier-y2(in-back);
+$in-back-r-value: reverse-bezier-value(in-back);
+
+$in-back: get-bezier('in-back', $in-back-value);
+$ease-in-back: $in-back;
+$in-back-r: get-bezier('in-back-r', $in-back-r-value);
+$ease-in-back-r: $in-back-r;
+
+// out-back
+
+$out-back-value: bezier-x1(out-back), bezier-y1(out-back), bezier-x2(out-back), bezier-y2(out-back);
+$out-back-r-value: reverse-bezier-value(out-back);
+
+$out-back: get-bezier('out-back', $out-back-value);
+$ease-out-back: $out-back;
+$out-back-r: get-bezier('out-back-r', $out-back-r-value);
+$ease-out-back-r: $out-back-r;
+
+// in-out-back
+
+$in-out-back-value: bezier-x1(in-out-back), bezier-y1(in-out-back), bezier-x2(in-out-back), bezier-y2(in-out-back);
+$in-out-back-r-value: reverse-bezier-value(in-out-back);
+
+$in-out-back: get-bezier('in-out-back', $in-out-back-value);
+$ease-in-out-back: $in-out-back;
+$in-out-back-r: get-bezier('in-out-back-r', $in-out-back-r-value);
+$ease-in-out-back-r: $in-out-back-r;
diff --git a/src/easings/easings.scss b/src/easings/easings.scss
index ee8f02e..a47aabe 100644
--- a/src/easings/easings.scss
+++ b/src/easings/easings.scss
@@ -1,105 +1,3 @@
-@import 'in-sine';
-@import 'out-sine';
-@import 'in-out-sine';
-
-@import 'in-quad';
-@import 'out-quad';
-@import 'in-out-quad';
-
-@import 'in-cubic';
-@import 'out-cubic';
-@import 'in-out-cubic';
-
-@import 'in-quart';
-@import 'out-quart';
-@import 'in-out-quart';
-
-@import 'in-quint';
-@import 'out-quint';
-@import 'in-out-quint';
-
-@import 'in-expo';
-@import 'out-expo';
-@import 'in-out-expo';
-
-@import 'in-circ';
-@import 'out-circ';
-@import 'in-out-circ';
-
-@import 'in-back';
-@import 'out-back';
-@import 'in-out-back';
-
-/**
- * The value associated to each easing
- */
-$easings-map: (
-  'in-sine': $in-sine-value,
-  'out-sine': $out-sine-value,
-  'in-out-sine': $in-out-sine-value,
-
-  'in-quad': $in-quad-value,
-  'out-quad': $out-quad-value,
-  'in-out-quad': $in-out-quad-value,
-
-  'in-cubic': $in-cubic-value,
-  'out-cubic': $out-cubic-value,
-  'in-out-cubic': $in-out-cubic-value,
-
-  'in-quart': $in-quart-value,
-  'out-quart': $out-quart-value,
-  'in-out-quart': $in-out-quart-value,
-
-  'in-quint': $in-quint-value,
-  'out-quint': $out-quint-value,
-  'in-out-quint': $in-out-quint-value,
-
-  'in-expo': $in-expo-value,
-  'out-expo': $out-expo-value,
-  'in-out-expo': $in-out-expo-value,
-
-  'in-circ': $in-circ-value,
-  'out-circ': $out-circ-value,
-  'in-out-circ': $in-out-circ-value,
-
-  'in-back': $in-back-value,
-  'out-back': $out-back-value,
-  'in-out-back': $in-out-back-value,
-);
-
-/**
- * Available easings
- */
-$easings-list: (
-  'in-sine',
-  'out-sine',
-  'in-out-sine',
-
-  'in-quad',
-  'out-quad',
-  'in-out-quad',
-
-  'in-cubic',
-  'out-cubic',
-  'in-out-cubic',
-
-  'in-quart',
-  'out-quart',
-  'in-out-quart',
-
-  'in-quint',
-  'out-quint',
-  'in-out-quint',
-
-  'in-expo',
-  'out-expo',
-  'in-out-expo',
-
-  'in-circ',
-  'out-circ',
-  'in-out-circ',
-
-  'in-back',
-  'out-back',
-  'in-out-back',
-);
+@import 'timings';
+@import 'variables';
+@import 'list-and-mapping';
diff --git a/src/functions/_bezier.scss b/src/functions/_bezier.scss
new file mode 100644
index 0000000..4822f64
--- /dev/null
+++ b/src/functions/_bezier.scss
@@ -0,0 +1,42 @@
+/**
+ * ALIAS FOR THE CSS cubic-bezier FUNCTION
+ *
+ * Use:
+ * `transition-timing-function: bezier(.1, .02, 1, .7);`
+ */
+@function bezier($args...) {
+  @return #{'cubic-bezier(#{$args})'};
+}
+
+/**
+ * REVERSE A cubic-bezier TIMING FUNCTION
+ *
+ * Use:
+ * `transition-timing-function: reverse-bezier(.1, .02, 1, .7);`
+ * `transition-timing-function: reverse-bezier($in-out-quad-value);`
+ */
+@function reverse-bezier($args...) {
+
+  // Turn single argument into 4 arguments
+  @if length($args) == 1 and length(nth($args, 1)) == 4 {
+    $args: nth($args, 1);
+  }
+
+  $x1: nth($args, 1);
+  $y1: nth($args, 2);
+  $x2: nth($args, 3);
+  $y2: nth($args, 4);
+
+  @return #{'cubic-bezier(#{1 - $x2}, #{1 - $y2}, #{1 - $x1}, #{1 - $y1})'};
+}
+
+/**
+ * ALIAS TO reverse-bezier
+ */
+@function r-bezier($args...) {
+  @if length($args) == 1 and length(nth($args, 1)) == 4 {
+    $args: nth($args, 1);
+  }
+
+  @return reverse-bezier($args);
+}
diff --git a/src/functions/_helpers.scss b/src/functions/_helpers.scss
new file mode 100644
index 0000000..31dfb1a
--- /dev/null
+++ b/src/functions/_helpers.scss
@@ -0,0 +1,46 @@
+/**
+ * RETURNS A cubic bezier TIMING FUNCTION.
+
+ * Modern browsers will get a custom property, legacy browsers will get a
+ * `cubic-bezier()` function.
+ */
+@function get-bezier($name, $value) {
+  @if variable-exists('easings-legacy') == false or $easings-legacy == false {
+    @return var(--#{$name});
+  } @else {
+    @return cubic-bezier($value);
+  }
+}
+
+/**
+ * RETURNS VALUE(S) FOR A NAMED TIMING FUNCTION.
+ */
+
+@function bezier-value($name, $coordinate) {
+  @return map-get(map-get($easings-values, $name), $coordinate);
+}
+
+@function reverse-bezier-value($name) {
+  $x1: bezier-x1($name);
+  $y1: bezier-y1($name);
+  $x2: bezier-x2($name);
+  $y2: bezier-y2($name);
+
+  @return 1 - $x2, 1 - $y2, 1 - $x1, 1 - $y1;
+}
+
+@function bezier-x1($name) {
+  @return bezier-value($name, 'x1');
+}
+
+@function bezier-y1($name) {
+  @return bezier-value($name, 'y1');
+}
+
+@function bezier-x2($name) {
+  @return bezier-value($name, 'x2');
+}
+
+@function bezier-y2($name) {
+  @return bezier-value($name, 'y2');
+}
diff --git a/src/functions/bezier.scss b/src/functions/bezier.scss
deleted file mode 100644
index f723e38..0000000
--- a/src/functions/bezier.scss
+++ /dev/null
@@ -1,23 +0,0 @@
-/**
- * RETURNS A cubic bezier TIMING FUNCTION.
-
- * Modern browsers will get a custom property, legacy browsers will get a
- * `cubic-bezier()` function.
- */
-@function get-bezier($name, $value) {
-  @if variable-exists('easings-legacy') == false or $easings-legacy == false {
-    @return var(--#{$name});
-  } @else {
-    @return cubic-bezier($value);
-  }
-}
-
-/**
- * ALIAS FOR THE CSS cubic-bezier FUNCTION
- *
- * Use:
- * `transition-timing-function: bezier(.1, .02, 1, .7);`
- */
-@function bezier($args...) {
-  @return #{'cubic-bezier(#{$args})'};
-}
diff --git a/src/functions/functions.scss b/src/functions/functions.scss
new file mode 100644
index 0000000..d1b096f
--- /dev/null
+++ b/src/functions/functions.scss
@@ -0,0 +1,2 @@
+@import 'helpers';
+@import 'bezier';