diff --git a/game/rules.fnl b/game/rules.fnl
index 76fe437..2bf1afc 100644
--- a/game/rules.fnl
+++ b/game/rules.fnl
@@ -140,7 +140,16 @@
 
 (fn Rules.rotate [di]
   (when state.current
-    (set state.current.irotation (+ state.current.irotation di))))
+    (var settled false)
+    (let [irotation (+ state.current.irotation di)
+          tetromino (Rules.tetromino state.current.piece irotation)]
+      (each [_ dx (ipairs [0 1 -1]) :until settled]
+        (let [x (+ state.current.x dx)
+              y state.current.y]
+          (when (not (Rules.collides? tetromino x y))
+            (set settled true)
+            (set state.current.x x)
+            (set state.current.irotation irotation)))))))
 
 (set Rules.commands
   {:move Rules.try-move-piece
diff --git a/game/tilemap.fnl b/game/tilemap.fnl
index c1385de..1ebe98e 100644
--- a/game/tilemap.fnl
+++ b/game/tilemap.fnl
@@ -21,8 +21,8 @@
 (fn set-itile-at [x y tilemap itile]
   (let [row (or (. tilemap (+ y 1)) "")
         row (.. row (string.rep " " (math.max 0 (- x (length row)))))
-        pre (row:sub 1 (- x 1))
-        post (row:sub (+ x 1))
+        pre (row:sub 1 x)
+        post (row:sub (+ x 2))
         row (.. pre itile post)]
     (tset tilemap (+ y 1) row)))