diff --git a/haskell/Main.hs b/haskell/Main.hs
index 3678f01..830ffd3 100644
--- a/haskell/Main.hs
+++ b/haskell/Main.hs
@@ -23,7 +23,7 @@ main :: IO ()
 main = do
     -- terminalWidth <- Terminal.Size.width <<$>> Terminal.Size.size -- TODO this doesn't work in GHCID or GHCIWatch...
     terminalWidth <- pure $ Just 62
-    putStrLn $ drawTree $ T.unpack <$> getTestTree tests
+    T.putStrLn $ drawTree $ getTestTree tests
     TL.putStrLn . displayTestResultsConsole terminalWidth =<< runTests () tests
 
 tests :: TestTree IO ()
diff --git a/haskell/Pre.hs b/haskell/Pre.hs
index d31b7c7..e9b46c5 100644
--- a/haskell/Pre.hs
+++ b/haskell/Pre.hs
@@ -184,18 +184,19 @@ adjacentPairs = \case
 sortPair :: (Ord a) => (a, a) -> (a, a)
 sortPair (a, b) = if a <= b then (a, b) else (b, a)
 
--- | This is `Data.Tree.drawTree` with the ASCII characters replaced with Unicode box drawing characters.
-drawTree :: Tree String -> String
-drawTree = unlines . draw
+-- | This is `Data.Tree.drawTree` with the ASCII characters replaced with Unicode box drawing characters,
+-- and using `Text` instead of `String`.
+drawTree :: Tree Text -> Text
+drawTree = T.unlines . draw
   where
-    draw (Node x ts0) = lines x ++ drawSubTrees ts0
+    draw (Node x ts0) = T.lines x <> drawSubTrees ts0
       where
         drawSubTrees [] = []
         drawSubTrees [t] =
             "│" : shift_ "└─ " "   " (draw t)
         drawSubTrees (t : ts) =
-            "│" : shift_ "├─ " "│  " (draw t) ++ drawSubTrees ts
-        shift_ first_ other = zipWith (++) (first_ : repeat other)
+            "│" : shift_ "├─ " "│  " (draw t) <> drawSubTrees ts
+        shift_ first_ other = zipWith (<>) (first_ : repeat other)
 
 type PuzzleParts input = HListF ((Fanout ((->) input) (Op Text)))
 infixr 9 /\\