diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## 0.2.2
+
+- Added cubicHermite.
+
+## 0.2.1
+
+- Added unspline.
+
 ## 0.2
 
 - Function 'smooth' has a new name; 'sample'.
diff --git a/smoothie.cabal b/smoothie.cabal
--- a/smoothie.cabal
+++ b/smoothie.cabal
@@ -1,5 +1,5 @@
 name:                smoothie
-version:             0.2.1
+version:             0.2.2
 synopsis:            Smooth curves via several splines and polynomials.
 description:         This package exports several splines and curves you can use
                      to interpolate points in between.
diff --git a/src/Data/Spline/Polynomial.hs b/src/Data/Spline/Polynomial.hs
--- a/src/Data/Spline/Polynomial.hs
+++ b/src/Data/Spline/Polynomial.hs
@@ -17,6 +17,7 @@
   , linear
   , linearBy
   , cosine
+  , cubicHermite
     -- * Helpers
   , bsearchLower
   ) where
@@ -80,6 +81,12 @@
 -- |Cosine polynomial.
 cosine :: (Additive a,Floating s,Ord s) => Polynomial s (a s)
 cosine = linearBy $ \x -> (1 - cos (x * pi)) * 0.5
+
+-- |Cubic hermite interpolation.
+--
+-- Implemented with https://en.wikipedia.org/wiki/Smoothstep.
+cubicHermite :: (Additive a,Fractional s,Ord s) => Polynomial s (a s)
+cubicHermite = linearBy $ \x -> x * x * (3 - 2 * x)
 
 -- |Helper binary search that search the ceiling index for the
 -- value to be searched according to the predicate.