diff --git a/simalq/tile/monster.hy b/simalq/tile/monster.hy
index 7b1c352..067c540 100644
--- a/simalq/tile/monster.hy
+++ b/simalq/tile/monster.hy
@@ -418,7 +418,7 @@
       :points-for-generator (classmethod (fn [cls] ~points-gen))
       :flavor ~flavor-mon
       :flavor-for-generator ~flavor-gen
-      ~@(sum :start [] (gfor
+      ~@(hy.I.toolz.concat (gfor
         [k v] (.items kwargs)
         [(hy.models.Keyword k) v])))
 
diff --git a/simalq/tile/tilepedia.hy b/simalq/tile/tilepedia.hy
index faa61e4..f96410c 100644
--- a/simalq/tile/tilepedia.hy
+++ b/simalq/tile/tilepedia.hy
@@ -2,6 +2,7 @@
 
 
 (import
+  toolz [concat]
   metadict [MetaDict]
   simalq.color
   simalq.game-state [G]
@@ -97,9 +98,9 @@
             :href (+ "#" tile.id)))))))))
 
     ; One section of info screens per superclass
-    #* (cat (gfor
+    #* (concat (gfor
       [superclass-name tiles] (.items info)
-      [(E.h2 superclass-name) #* (cat (gfor
+      [(E.h2 superclass-name) #* (concat (gfor
         ; One info screen per tile type
         tile tiles
         [(E.h3 (mapsym tile) tile.long-name :id tile.id)
@@ -131,9 +132,5 @@
     (if self-closing "" f"</{(hesc tag)}>")))
 
 
-(defn cat [l]
-  (sum :start [] l))
-
-
 (when (= __name__ "__main__")
   (print (html)))
diff --git a/tests/lib.hy b/tests/lib.hy
index 30431ed..89e02ef 100644
--- a/tests/lib.hy
+++ b/tests/lib.hy
@@ -5,6 +5,7 @@
 (require
   hyrule [do-n unless])
 (import
+  toolz [concat]
   metadict [MetaDict]
   simalq.geometry [Pos at Direction]
   simalq.un-iq [iq-quest]
@@ -82,7 +83,8 @@
     (hy.I.simalq/tile.Player :pos (Pos model player-x player-y)))
   (assert (= G.map.width model.width))
   (assert (= G.map.height model.height))
-  (for [[stack-actual stack-expected] (zip (sum :start #() G.map.data) (sum :start #() model.data))]
+  (for [[stack-actual stack-expected]
+      (zip (concat G.map.data) (concat model.data))]
     (assert (= (len stack-actual) (len stack-expected)))
     (for [[t-actual t-expected] (zip stack-actual stack-expected)]
       (assert (= t-actual.stem t-expected.stem)))))