diff --git a/demo2.cpp b/demo2.cpp
index 83ca4b7..1f8b4ea 100644
--- a/demo2.cpp
+++ b/demo2.cpp
@@ -39,6 +39,10 @@
        memory and turning can be less precise (can be seen a lot with 64 item
        LUT). */
 
+#define DOOR_ROLL_SIGN -1
+  /* ^ Defines how the door roll: -1 opens the door to the left, 1 to the
+       right, 0 to both. */
+
 #define FPS 60
 #define HEAD_BOB_HEIGHT 200
 #define HEAD_BOB_STEP 20
@@ -902,7 +906,7 @@ Unit rollAt(int16_t x, int16_t y)
 
   if (x >= 0 && x < LEVEL_X_RES && y >= 0 && y < LEVEL_Y_RES &&
     level[(LEVEL_Y_RES - y -1) * LEVEL_X_RES + x] == 6)
-    return (pokitto.frameCount * 10) % UNITS_PER_SQUARE; 
+    return sinInt(pokitto.frameCount * 10) + DOOR_ROLL_SIGN * UNITS_PER_SQUARE; 
 
   return 0;
 }