diff --git a/Graphics/Diagram/Gif.hs b/Graphics/Diagram/Gif.hs
index 2e29499..80c3ecb 100644
--- a/Graphics/Diagram/Gif.hs
+++ b/Graphics/Diagram/Gif.hs
@@ -4,8 +4,9 @@ module Graphics.Diagram.Gif where
 
 import Algebra.VectorTypes
 import Codec.Picture.Gif
+import Data.Monoid
 import Diagrams.Backend.Cairo
-import Diagrams.Prelude
+import Diagrams.Prelude hiding ((<>))
 import Graphics.Diagram.Plotter
 import Graphics.Diagram.Types
 import Parser.Meshparser
@@ -16,7 +17,7 @@ gifDiag :: DiagProp -> [PT] -> [(Diagram Cairo R2, GifDelay)]
 gifDiag p xs =
   fmap ((\x -> (x, 100)) . (<> nonChDiag))      .
     flip (++)
-      [mkDiag (convexHPText `mappend`
+      [mkDiag (convexHPText <>
         convexHP)
         p xs <> lastUpperHull <> lastLowerHull] $
     (lowerHullList ++ ((<> lastLowerHull) <$> upperHullList))
diff --git a/Graphics/Diagram/Plotter.hs b/Graphics/Diagram/Plotter.hs
index 5010abc..969b406 100644
--- a/Graphics/Diagram/Plotter.hs
+++ b/Graphics/Diagram/Plotter.hs
@@ -5,8 +5,9 @@ module Graphics.Diagram.Plotter where
 import Algebra.Vector
 import Algebra.VectorTypes
 import Algorithms.ConvexHull.GrahamScan
+import Data.Monoid
 import Diagrams.Backend.Cairo
-import Diagrams.Prelude
+import Diagrams.Prelude hiding ((<>))
 import Graphics.Diagram.Types
 
 
@@ -121,8 +122,8 @@ convexUHStepsLs = convexHStepsLs purple grahamUHSteps
 -- by the dimensions given in xD from DiagProp.
 xAxis :: Diag
 xAxis =
-  Diag hRule      `mappend`
-    Diag segments `mappend`
+  Diag hRule      <>
+    Diag segments <>
     Diag labels
   where
     hRule p _ =
@@ -149,8 +150,8 @@ xAxis =
 -- by the dimensions given in yD from DiagProp.
 yAxis :: Diag
 yAxis =
-  Diag vRule      `mappend`
-    Diag segments `mappend`
+  Diag vRule      <>
+    Diag segments <>
     Diag labels
   where
     vRule p _ =
@@ -193,7 +194,7 @@ whiteRect x y = rect x y # lwG 0.00 # bg white
 -- |Create a grid across the whole diagram with squares of the
 -- given size in DiagProp.
 grid :: Diag
-grid = Diag xGrid `mappend` Diag yGrid
+grid = Diag xGrid <> Diag yGrid
   where
     yGrid p _ =
       hcat' (with & sep .~ sqS p)