diff --git a/src/Stream.hs b/src/Stream.hs
index 2d1b5d7..1de142d 100644
--- a/src/Stream.hs
+++ b/src/Stream.hs
@@ -10,10 +10,12 @@ import Data.List (intercalate)
 
 data Stream a = Stream [(a, Stream a)] deriving Show
 
-instance Monoid (Stream a) where
-  mempty = fromList []
-  mappend (Stream []) b = b
-  mappend (Stream pairs) b = Stream $ (\(a, stream) -> (a, stream `mappend` b)) <$> pairs
+empty :: Stream a
+empty = fromList []
+
+append :: Stream a -> Stream a -> Stream a
+append (Stream []) b = b
+append (Stream pairs) b = Stream $ (\(a, stream) -> (a, stream `append` b)) <$> pairs
 
 fromList :: [a] -> Stream a
 fromList [] = Stream []