diff --git a/lib/ClassicTileDfn.js b/lib/ClassicTileDfn.js
index 45b661c..de8580e 100644
--- a/lib/ClassicTileDfn.js
+++ b/lib/ClassicTileDfn.js
@@ -57,7 +57,7 @@ ltjs.ClassicTileDfn = Class( 'ClassicTileDfn' )
             [ 'water',    0 ], /* water alt 2 */
             [ 'atdownb',  1 ], /* anti-tank, blown up, down */
             [ 'block',    0 ], /* non-movable block */
-            [ 'mblock',   0 ], /* movable block */
+            [ 'mblock',   1 ], /* movable block */
             [ 'brick',    0 ], /* brick */
             [ 'atup',     1 ], /* anti-tank up */
             [ 'atup',     1 ], /* anti-tank up alt */