diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # recursion
 
+## 1.1.0.0
+
+* Add `NonEmptyF` and relevant instances
+* Add `chema` for mutual recursion
+* Drop support for GHC 7.10.3
+
+## 1.0.0.0
+
+* Rewrite completely in the style of `recursion-schemes`, making type inference
+better.
+
 ## 0.1.1.0
 
 * Add `dicata`
diff --git a/recursion.cabal b/recursion.cabal
--- a/recursion.cabal
+++ b/recursion.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.18
 name: recursion
-version: 1.0.0.0
+version: 1.1.0.0
 license: BSD3
 license-file: LICENSE
 copyright: Copyright: (c) 2018 Vanessa McHale
@@ -36,7 +36,7 @@
                       ExistentialQuantification RankNTypes TypeFamilies
     ghc-options: -Wall
     build-depends:
-        base >=4.8 && <5,
+        base >=4.9 && <5,
         composition-prelude -any
     
     if flag(development)
diff --git a/src/Control/Recursion.hs b/src/Control/Recursion.hs
--- a/src/Control/Recursion.hs
+++ b/src/Control/Recursion.hs
@@ -14,6 +14,7 @@
     , Mu (..)
     , Nu (..)
     , ListF (..)
+    , NonEmptyF (..)
     -- * Recursion schemes
     , hylo
     , prepro
@@ -28,6 +29,8 @@
     , meta
     , meta'
     , dicata
+    -- * Mutual recursion
+    , chema
     -- * Mendler-style recursion schemes
     , mhisto
     , mcata
@@ -38,16 +41,22 @@
     -- * Helper functions
     , lambek
     , colambek
+    -- * Helper types
+    , Lens'
     ) where
 
 import           Control.Arrow       ((&&&))
 import           Control.Composition ((.*), (.**))
 import           Control.Monad       ((<=<))
+import           Data.Foldable       (toList)
+import           Data.List.NonEmpty  (NonEmpty (..))
+import qualified Data.List.NonEmpty  as NE
 import           Numeric.Natural     (Natural)
 
 type family Base t :: * -> *
 
 class (Functor (Base t)) => Recursive t where
+
     project :: t -> Base t t
 
     -- | Catamorphism. Folds a structure. (see [here](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.41.125&rep=rep1&type=pdf))
@@ -56,6 +65,7 @@
 
 
 class (Functor (Base t)) => Corecursive t where
+
     embed :: Base t t -> t
 
     -- | Anamorphism, meant to build up a structure recursively.
@@ -67,12 +77,18 @@
                | Nil
                deriving (Functor)
 
+data NonEmptyF a b = NonEmptyF a (Maybe b)
+    deriving (Functor)
+
 newtype Fix f = Fix { unFix :: f (Fix f) }
 
 data Nu f = forall a. Nu (a -> f a) a
 
 newtype Mu f = Mu (forall a. (f a -> a) -> a)
 
+-- | A map of \\( F \\)-coalgebras
+type Lens' s a = forall f . Functor f => (a -> f a) -> s -> f s
+
 type instance Base (Fix f) = f
 
 type instance Base (Mu f) = f
@@ -83,6 +99,8 @@
 
 type instance Base [a] = ListF a
 
+type instance Base (NonEmpty a) = NonEmptyF a
+
 instance Recursive Natural where
     project 0 = Nothing
     project n = Just (n-1)
@@ -113,6 +131,14 @@
     embed Nil         = []
     embed (Cons x xs) = x : xs
 
+instance Recursive (NonEmpty a) where
+    project (x :| []) = NonEmptyF x Nothing
+    project (x :| xs) = NonEmptyF x (Just (NE.fromList xs))
+
+instance Corecursive (NonEmpty a) where
+    embed (NonEmptyF x Nothing)   = x :| []
+    embed (NonEmptyF x (Just xs)) = x :| toList xs
+
 -- | Hylomorphism; fold a structure while buildiung it up.
 hylo :: Functor f => (f b -> b) -> (a -> f a) -> a -> b
 hylo f g = h where h = f . fmap h . g
@@ -192,3 +218,11 @@
 -- | Apomorphism
 apo :: (Corecursive t) => (a -> Base t (Either t a)) -> a -> t
 apo g = a where a = embed . fmap (either id a) . g
+
+-- Entangle two anamorphisms.
+chema :: (Corecursive t')
+      => ((a -> f a) -> Lens' b b) -- ^ A lens parametric in an \\( F \\)-coalgebra that allows @b@ to inspect itself.
+      -> (a -> f a) -- ^ A @(Base t)@-coalgebra
+      -> (b -> Base t' b) -- ^ A @(Base t')@-coalgebra
+      -> b -> t'
+chema = (ana .*)