diff --git a/projects/asciilib2/src/asciilib/Surface.kiss b/projects/asciilib2/src/asciilib/Surface.kiss
index 6083c78c..cc7bbb6a 100644
--- a/projects/asciilib2/src/asciilib/Surface.kiss
+++ b/projects/asciilib2/src/asciilib/Surface.kiss
@@ -35,9 +35,9 @@
 // TODO rectangle type
 // TODO optional source rectangle argument
 (defmethod blitSurface [:Surface surface x y]
-    (doFor [srcX destX] (zipDrop (range surface.width) (range x (+ x surface.width)))
+    (doFor [srcX destX] (the kiss.List<kiss.List<Int>> (zipDrop (range surface.width) (range x (+ x surface.width))))
         (when (< -1 destX width)
-            (doFor [srcY destY] (zipDrop (range 0 surface.height) (range y (+ y surface.height)))
+            (doFor [srcY destY] (the kiss.List<kiss.List<Int>> (zipDrop (range 0 surface.height) (range y (+ y surface.height))))
                 (when (< -1 destY height)
                     (when (surface.isCellOpaque srcX srcY)
                         (setBackgroundColor destX destY (surface.getBackgroundColor srcX srcY))