diff --git a/circuitflow.cabal b/circuitflow.cabal
index 6ee33b6..af844df 100644
--- a/circuitflow.cabal
+++ b/circuitflow.cabal
@@ -73,6 +73,7 @@ library
     , directory
   hs-source-dirs: src
   default-language: Haskell2010
+  ghc-options: -fprint-potential-instances -freduction-depth=201
 
 test-suite test
   default-language: Haskell2010
diff --git a/src/Pipeline/Circuit.hs b/src/Pipeline/Circuit.hs
index 615b34f..4e29418 100644
--- a/src/Pipeline/Circuit.hs
+++ b/src/Pipeline/Circuit.hs
@@ -8,6 +8,8 @@ Maintainer  : haskell@rly.rocks
 This package contains all the constructors needed to build a 'Circuit'.
 
 -}
+
+{-# LANGUAGE UndecidableInstances #-}
 module Pipeline.Circuit
   (
   -- * Main Type
@@ -23,6 +25,7 @@ module Pipeline.Circuit
   , dropL
   , dropR
   , mapC
+  , replicateInputs
   ) where
 
 
@@ -30,8 +33,8 @@ import           Pipeline.Internal.Common.IFunctor         (IFix5 (..))
 import           Pipeline.Internal.Common.IFunctor.Modular ((:<:) (..))
 import           Pipeline.Internal.Common.Nat              (IsNat, N1, N2,
                                                             Nat (..), SNat (..), (:+))
-import           Pipeline.Internal.Common.TypeList         (Apply, Drop, Length,
-                                                            Take, Replicate, (:++))
+import           Pipeline.Internal.Common.TypeList         (Apply, Drop, Length, Swap, Pair, Transpose, Concat,
+                                                            Take, Replicate, Duplicate, (:++))
 import qualified Pipeline.Internal.Core.CircuitAST as AST
 import           Pipeline.Internal.Core.DataStore          (DataStore,
                                                             DataStore', Var)
@@ -169,5 +172,91 @@ instance (DataStore f a, Eq a, Eq (f a)) => ReplicateN ('Succ ('Succ 'Zero)) f a
 instance (DataStore f a, Eq a, Eq (f a)) => ReplicateN ('Succ ('Succ ('Succ 'Zero))) f a where
   replicateN (SSucc n) = replicate2 <-> id <> replicateN n
 
-replicateMany :: SNat m -> AST.Circuit fs as (fs :++ fs) (as :++ as) m
-replicateMany = undefined
+
+class (DataStore' fs as) => ReplicateInputs m fs as where
+  replicateInputs :: ( Length fs ~ m
+                     , Length as ~ m
+                     , Length (Duplicate fs) ~ Length (Duplicate as)
+                     , ('Succ 'Zero :+ m) ~ 'Succ m
+                     , IsNat m
+                     ) => SNat m -> AST.Circuit fs as (Duplicate fs) (Duplicate as) m
+
+instance (DataStore f a, Eq a, Eq (f a)) => ReplicateInputs ('Succ 'Zero) '[f] '[a] where
+  replicateInputs (SSucc SZero) = replicate2
+
+instance ( DataStore f a
+         , DataStore' fs as
+         , DataStore' (Duplicate fs) (Duplicate as)
+         , ReplicateInputs ('Succ n) fs as
+         , Length fs ~ 'Succ n
+         , IsNat n
+         , Eq a
+         , Eq (f a)
+         ) => ReplicateInputs ('Succ ('Succ n)) (f ': fs) (a ': as) where
+  replicateInputs (SSucc (SSucc n)) = replicate2 <> replicateInputs (SSucc n)
+
+class DataStore' fs as => OrganiseInputs m fs as where
+  organiseInputs :: SNat m
+    -> AST.Circuit fs
+                    as
+                    (Concat (Transpose (Pair fs)))
+                    (Concat (Transpose (Pair as)))
+                    (Length fs)
+
+instance (DataStore f a, DataStore g b, Eq a, Eq (f a), Eq b, Eq (g b)) => OrganiseInputs ('Succ 'Zero) '[f, g] '[a, b] where
+  organiseInputs (SSucc SZero) = id <> id
+
+-- Problem with the type as I need it to be something like f ': (fs :++ '[g])
+-- function peels one off each end of the list, which can't do with Haskell list!
+-- Any other way to write a function that does the same thing...?
+-- Currently its 'centre-recursive', a tail-recursive function would probably avoid the problem
+instance (DataStore f a, DataStore' fs as, Eq a, Eq (f a)) => OrganiseInputs ('Succ ('Succ n)) (f ': fs) (a ': as) where
+  organiseInputs = undefined -- Stuck here
+
+-- organiseInputs :: (DataStore' fs as) => SNat n
+--  -> AST.Circuit fs
+--                 as
+--                 (Concat (Transpose (Pair fs)))
+--                 (Concat (Transpose (Pair as)))
+--                 (Length fs)
+-- organiseInputs (SSucc SZero) = id <> id
+-- organiseInputs (SSucc n) = (id <> swapInputs     n <> id
+--                         <-> id <> organiseInputs n <> id)
+
+class DataStore' fs as => SwapInputs n fs as where
+  swapInputs :: SNat n -> AST.Circuit fs as (Swap n fs) (Swap n as) (Length fs)
+
+instance (DataStore f a, DataStore g b, Eq b, Eq (g b), Eq a, Eq (f a)) => SwapInputs ('Succ 'Zero) '[f, g] '[a, b] where
+  swapInputs (SSucc SZero) = swap
+
+instance ( DataStore f a
+         , DataStore g b
+         , SwapInputs ('Succ n) hs cs
+         , Length hs ~ Length cs
+         , Length (Swap ('Succ n) hs) ~ Length (Swap ('Succ n) cs)
+         , (N2 :+ Length cs) ~ 'Succ ('Succ (Length cs))
+         , (DataStore' (Swap ('Succ n) hs) (Swap ('Succ n) cs))
+         , IsNat (Length cs)
+         , Eq b, Eq (g b)
+         , Eq a, Eq (f a)
+         ) => SwapInputs ('Succ ('Succ n)) (f ': g ': hs) (a ': b ': cs) where
+  swapInputs (SSucc n) = swap <> swapInputs n
+
+replicateMany :: ( 'Succ 'Zero :+ m ~ 'Succ m
+                 , Length fs ~ m
+                 , Length as ~ m
+                 , Length (Apply fs as) ~ m
+                 , Length (Duplicate fs) ~ Length (Duplicate as)
+                 , (as :++ as) ~ Concat (Transpose (Pair (Duplicate as)))
+                 , (fs :++ fs) ~ Concat (Transpose (Pair (Duplicate fs)))
+                 , ReplicateInputs m fs as
+                 , OrganiseInputs m (Duplicate fs) (Duplicate as)
+                 , IsNat m
+                 , DataStore' (Duplicate fs) (Duplicate as)
+                 , DataStore' fs as
+                 , DataStore' (Concat (Transpose (Pair (Duplicate fs)))) (Concat (Transpose (Pair (Duplicate as))))
+                 ) => SNat m -> AST.Circuit fs as (fs :++ fs) (as :++ as) m
+replicateMany n = replicateInputs n
+                  <->
+                  organiseInputs n
+  -- where
diff --git a/src/Pipeline/Internal/Common/TypeList.hs b/src/Pipeline/Internal/Common/TypeList.hs
index 3a210b7..0e7ecc3 100644
--- a/src/Pipeline/Internal/Common/TypeList.hs
+++ b/src/Pipeline/Internal/Common/TypeList.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE UndecidableInstances #-}
 module Pipeline.Internal.Common.TypeList where
 
 import           Pipeline.Internal.Common.Nat (Nat (..))
@@ -33,3 +34,34 @@ type family Apply (fs :: [Type -> Type]) (as :: [Type]) where
 type family Replicate (n :: Nat) (a :: k) :: [k] where
   Replicate 'Zero _ = '[]
   Replicate ('Succ n) x = x ': Replicate n x
+
+type family Duplicate (a :: [k]) :: [k] where
+  Duplicate '[] = '[]
+  Duplicate (x ': xs) = x ': x ': Duplicate xs
+
+type family Swap (n :: Nat) (a :: [k]) :: [k] where
+  Swap n     '[] = '[]
+  Swap 'Zero l   = l
+  Swap ('Succ n) (x ': y ': xs) = y ': x ': Swap n xs
+
+
+type family Pair (xs :: [k]) :: [[k]] where
+  Pair '[] = '[]
+  Pair (x ': y ': xs) = '[x, y] ': Pair xs
+
+type family Concat (xss :: [[k]]) :: [k] where
+  Concat '[] = '[]
+  Concat ('[] ': l) = Concat l
+  Concat ((x ': xs) ': l) = x ': Concat (xs ': l)
+
+type family Transpose (xss :: [[k]]) :: [[k]] where
+  Transpose ('[] ': _) = '[]
+  Transpose xss = Heads xss ': Transpose (Tails xss)
+
+type family Heads (xss :: [[k]]) :: [k] where
+  Heads '[] = '[]
+  Heads ((x ': xs) ': xss) = x ': Heads xss
+  
+type family Tails (xss :: [[k]]) :: [[k]] where
+  Tails '[] = '[]
+  Tails ((x ': xs) ': xss) = xs ': Tails xss
diff --git a/src/Pipeline/Internal/Core/CircuitAST.hs b/src/Pipeline/Internal/Core/CircuitAST.hs
index 6e5604b..c57fc81 100644
--- a/src/Pipeline/Internal/Core/CircuitAST.hs
+++ b/src/Pipeline/Internal/Core/CircuitAST.hs
@@ -23,8 +23,8 @@ import           Pipeline.Internal.Common.IFunctor         (IFix5 (..),
 import           Pipeline.Internal.Common.IFunctor.Modular ((:+:) (..))
 import           Pipeline.Internal.Common.Nat              (IsNat (..), N1, N2,
                                                             Nat (..), (:+),
-                                                            (:=))
-import           Pipeline.Internal.Common.TypeList         (Apply, Drop, Length,
+                                                            (:=), SNat (..))
+import           Pipeline.Internal.Common.TypeList         (Drop, Length,
                                                             Take, (:++))
 import           Pipeline.Internal.Core.DataStore          (DataStore,
                                                             DataStore', Var)
@@ -42,6 +42,13 @@ data Replicate (iF :: [Type -> Type] -> [Type] -> [Type -> Type] -> [Type] -> Na
   Replicate ::(DataStore' '[f] '[a])
     => Replicate iF '[f] '[a] [f, f] '[a, a] N1
 
+data ReplicateManyN (iF :: [Type -> Type] -> [Type] -> [Type -> Type] -> [Type] -> Nat -> Type)
+               (inputsS :: [Type -> Type]) (inputsT :: [Type])
+               (outputsS :: [Type -> Type]) (outputsT :: [Type]) (ninputs :: Nat) where
+  ReplicateManyN ::(DataStore' '[f] '[a])
+    => SNat n -> SNat m -> ReplicateManyN iF '[f] '[a] [f, f] '[a, a] N1
+
+
 data Then (iF :: [Type -> Type] -> [Type] -> [Type -> Type] -> [Type] -> Nat -> Type)
           (inputsS :: [Type -> Type]) (inputsT :: [Type])
           (outputsS :: [Type -> Type]) (outputsT :: [Type]) (ninputs :: Nat) where
diff --git a/tests/Pipeline/Network/MinimalTests.hs b/tests/Pipeline/Network/MinimalTests.hs
index c8d9102..e67ef3a 100644
--- a/tests/Pipeline/Network/MinimalTests.hs
+++ b/tests/Pipeline/Network/MinimalTests.hs
@@ -25,6 +25,7 @@ minimalTests = testGroup
   "Minimal Examples"
   [ idTests
   , replicate2Tests
+  , replicate3Tests
   , thenTests
   , besideTests
   , swapTests
@@ -33,6 +34,7 @@ minimalTests = testGroup
   , functionTaskTests
   , multiInputTaskTests
   , mapTests
+  , replicateInputsTests
   ]
 
 
@@ -84,7 +86,7 @@ replicate2Tests = testGroup
       out <- fetch' o
       out @?= HCons 0 (HCons 0 HNil)
   ]
-
+  
 replicate3Circuit
   :: Circuit
        '[Var]
@@ -104,6 +106,28 @@ replicate3Tests = testGroup
       out <- fetch' o
       out @?= HCons 0 (HCons 0 (HCons 0 HNil))
   ]
+
+
+replicateInputsCircuit
+  :: Circuit
+       '[Var , Var]
+       '[Int , Int]
+       '[Var , Var , Var , Var]
+       '[Int , Int , Int , Int]
+       N2
+replicateInputsCircuit = replicateInputs (SSucc (SSucc SZero))
+
+replicateInputsTests :: TestTree
+replicateInputsTests = testGroup
+  "(replicateN 3) should"
+  [ testCase "return a trupled input value" $ do
+      var1 <- varWith 0
+      var2 <- varWith 2
+      let i = HCons' var1 (HCons' var2 HNil')
+      (Right o) <- singleInputTest replicateInputsCircuit i
+      out <- fetch' o
+      out @?= HCons 0 (HCons 0 (HCons 2 (HCons 2 HNil)))
+  ]
  
 -- Tests for the 'Then' constructor
 thenCircuit