diff --git a/hierarchical-clustering-diagrams.cabal b/hierarchical-clustering-diagrams.cabal
--- a/hierarchical-clustering-diagrams.cabal
+++ b/hierarchical-clustering-diagrams.cabal
@@ -1,5 +1,5 @@
 Name:                hierarchical-clustering-diagrams
-Version:             0.1.0.1
+Version:             0.2
 Synopsis:            Draw diagrams of dendrograms made by hierarchical-clustering.
 License:             BSD3
 License-file:        LICENSE
@@ -33,7 +33,7 @@
 
     , hierarchical-clustering == 0.4.*
 
-    , diagrams-lib            == 0.4.*
+    , diagrams-lib            == 0.5.*
   GHC-options: -Wall
 
 Test-suite runtests
@@ -45,8 +45,8 @@
 
     , hierarchical-clustering == 0.4.*
 
-    , diagrams-lib            == 0.4.*
-    , diagrams-cairo          == 0.4.*
+    , diagrams-lib            == 0.5.*
+    , diagrams-cairo          == 0.5.*
 
     , hspec                   == 0.9.*
     , HUnit                   == 1.2.*
diff --git a/src/Diagrams/Dendrogram.hs b/src/Diagrams/Dendrogram.hs
--- a/src/Diagrams/Dendrogram.hs
+++ b/src/Diagrams/Dendrogram.hs
@@ -12,7 +12,6 @@
     , fixedWidth
     , variableWidth
     , X
-    , hcatB
     ) where
 
 -- from base
@@ -68,11 +67,11 @@
 -- 'Width').
 --
 -- Note: you should probably use 'alignT' to align your items.
-dendrogram :: (Monoid m, Renderable (Path R2) b) =>
+dendrogram :: (Monoid m, Semigroup m, Renderable (Path R2) b) =>
               Width
-           -> (a -> AnnDiagram b R2 m)
+           -> (a -> QDiagram b R2 m)
            -> Dendrogram a
-           -> AnnDiagram b R2 m
+           -> QDiagram b R2 m
 dendrogram width_ drawItem dendro = (stroke path_ # value mempty)
                                                ===
                                          (items # alignL)
@@ -82,7 +81,7 @@
           Fixed -> let drawnItems = map drawItem (elements dendro)
                        w = width (head drawnItems)
                        (dendro', _) = fixedWidth w dendro
-                   in (dendrogramPath dendro', hcatB drawnItems)
+                   in (dendrogramPath dendro', hcat drawnItems)
           Variable -> first dendrogramPath $ variableWidth drawItem dendro
 
 
@@ -112,11 +111,11 @@
           (acc',  (!xL, !yL)) = go acc  l
           (acc'', (!xR, !yR)) = go acc' r
 
-          path = fromVertices [ P (xL, yL)
-                              , P (xL, d)
-                              , P (xR, d)
-                              , P (xR, yR)]
-          pos  = ((xL + xR) / 2, d)
+          path = fromVertices [ p2 (xL, yL)
+                              , p2 (xL, d)
+                              , p2 (xR, d)
+                              , p2 (xR, yR)]
+          pos  = (xL + (xR - xL) / 2, d)
 
 
 -- | The horizontal position of a dendrogram Leaf.
@@ -143,10 +142,10 @@
 -- resulting diagram having all 'Leaf'@s@ drawn side-by-side.
 --
 -- Note: you should probably use 'alignT' to align your items.
-variableWidth :: (Monoid m) =>
-                 (a -> AnnDiagram b R2 m)
+variableWidth :: (Semigroup m, Monoid m) =>
+                 (a -> QDiagram b R2 m)
               -> Dendrogram a
-              -> (Dendrogram X, AnnDiagram b R2 m)
+              -> (Dendrogram X, QDiagram b R2 m)
 variableWidth draw = finish . go 0 []
     where
       go !y acc (Leaf a) = (Leaf y', y'', dia : acc)
@@ -159,18 +158,8 @@
           where
             (l', !y',  acc'') = go y  acc' l -- yes, this is acc'
             (r', !y'', acc')  = go y' acc r
-      finish (dendro, _, dias) = (dendro, hcatB dias)
+      finish (dendro, _, dias) = (dendro, hcat dias)
       -- We used to concatenate diagrams inside 'go' using (|||).
       -- However, pathological dendrograms (such as those created
       -- using single linkage) may be highly unbalanced, creating
       -- a performance problem for 'variableWidth'.
-
-
--- | Like 'hcat', but balanced.  Much better performance.  Use it
--- for concatenating the items of your dendrogram.
-hcatB :: Monoid m => [AnnDiagram b R2 m] -> AnnDiagram b R2 m
-hcatB [y] = y
-hcatB ys  = hcatB $ dubs ys
-  where dubs (x1:x2:xs) = x1 ||| x2 : dubs xs
-        dubs [x]        = [x]
-        dubs []         = []