-Expandable wall expands in horizontal or vertical (or both) direction, if there
-is an empty space to fill up. You should be very careful not to be catched by
-the expanding wall.
+This wall will grow on either side that is open. It will stop
+growing on one side if it is blocked by a wall, even if said wall is later
+destroyed. Gems and others, however, will stop it only temporarily.
+
+This particular growing wall is the only one that is visibly different
+to the player from a normal wall, at least under the default graphics.